The Ultimate Guide: How To Fertilize Houseplants
Houseplant Fertilizer Guide Menu
Quickly navigate this page to find any topic without getting a sore finger
Do You Need To Feed Houseplants?
If you've ever wondered why we fertilize houseplants, the simple answer is to improve growth! Much like how we need energy to get through our days, our houseplants also need a bit of a nutritional boost. Fertilizing indoor plants gives them vital energy, vitamins, and minerals.
Think of the soil in your plant pots like a pantry. Over time, it can run out of the things that your plants require, and we have to replace them. Fertilizers top up these nutrients, like nitrogen for lush leaves, phosphorus for strong roots, and potassium for overall vitality. It's like giving your plants a healthy nutritional snack to keep them full in-between main meals, which is when we repot with fresh substrate to replenish nutrients.
Indoor conditions can be a bit challenging for plants. They don't get the natural nutrient cycling they would outside. Fertilizing helps mimic those natural conditions, ensuring your plants get what they need to grow well.
If you've got flowering houseplants or those that produce fruits, fertilizers can make all the difference. Ever noticed how some plants seem to bloom better with a little extra care? That's the magic of the right nutrients at work. Let's dive in!
Liquid plant fertilizer
How Often To Fertilize Indoor Plants
The frequency of fertilizing houseplants depends on the type of plant and the season. Flowering plants like Hoya, and fast growers like Ficus, may need more frequent feeding. Slow growing plants like cacti and succulents generally require feeding less frequently. Here's a general guide:
Growing Season — Spring and Summer:
Most houseplants benefit from being fertilized every 2–4 weeks during their active growth period. When plants are actively producing new leaves, stems, and roots, they require a steady supply of nutrients. For fast growers, we recommend a 2-week gap. For slow growers, we recommend a 4-week gap. With hungry, extremely fast-growing, or flowering plants, we have great experience feeding once a week to promote flowering, and to speed up growth.
Dormant Season — Autumn and Winter:
Most houseplants enter a period of slower growth in the darker months, so they don't need as many nutrients. Reduce fertilizing to once every 30 days. If you see signs of nutrient burn, stop feeding altogether. Our personal experience is slightly different to your average home, as we run a plant nursery with high levels of lighting. Our plants don't go fully dormant over the winter, so we continue to feed our plants with fertilizer. As a precaution, we dilute it with 50% more water for most feeds. If we see signs of issues, we skip feeding and use plain dechlorinated water.
Signs Your Plant Needs Feeding
Yellowing Leaves: Houseplants with yellow leaves may have a nutrient deficiency. Feed once a week and monitor for any difference in growth. Check soil and drainage holes as overwatering also causes this.
Slow Growth: If your plant isn't actively growing during spring and summer, it may need more nutrients.
Pale or Small Leaves: This may suggest that your plant requires a nutritional boost, or more lighting.
We have the black versions of this watering can in our office!
How To Prevent Overwatering With Moisture Meters
One of the hardest aspects of plant care for beginners is knowing when to water your houseplant. As we eat every day, it can be hard to imagine that a plant can go that long without food or attention, however, they can! As you become a more experienced plant keeper, you will learn how to judge the moisture within the soil by simply looking at the colour of it.
Another great way to tell when your plants need water is to lift the plant pot and feel how heavy it is. This is the method that we use here at the shop, and we highly recommend starting to test this as soon as possible in your plant journey. Start by lifting the pots before and after your scheduled watering to get a gauge of how heavy they should be. You may worry that you have too many houseplants to use this method, however, even with over 250 houseplants, we manage to tell instantly if they require water just by lifting each pot. This is more reliable than simply looking at the soil as sometimes, the top can e dry when the bottom is still wet, so it's not the most reliable method to tell if your plants require watering yet.
To remove any ambiguity, you can purchase either a mechanical removable moisture meter which you can carry around with you as you water. A more permanent solution for thirsty plants is to buy fixed watering spikes which live in the plant pot for a quick glance moisture reading. The most accurate way to read the moisture within the plant pot is to purchase a digital moisture meter, which gives you an instant, accurate reading of when you need to water your houseplants.
In-pot moisture meter
How To Feed Houseplants
Feeding plants is easy when you know how. There are a few effective techniques to water your houseplants, before we dive into choosing houseplant food, let's explore the best ways to give your plants fertilizer:
Top Watering: Fill the watering can with room temperature water. Pour water gently onto the soil until it's evenly moist. Ensure water drains out from the bottom. Check plants after 10–20 minutes and empty any excess water.
Bottom Watering: Fill a tray or basin with water. Place the plant pot in the tray, allowing it to absorb water from the bottom. Let it sit for 10–20 minutes, then drain the excess water to prevent root rot.
Applying Fertilizers Directly to Soil: Follow the fertilizer's instructions for the correct amount. For slow release granular fertilizers, sprinkle on soil and mix in gently with a hand trowel or your fingers.
Foliar Feeding: Provides nutrients directly to leaves, which prevents a build-up of mineral salts in soil. Mist leaves lightly with liquid fertilizer in a spray bottle, focusing on the undersides where stomata are located. To avoid leaf burn, mist in the morning or evening. Remember, foliar feeding is a supplemental method and doesn't replace soil watering. It's ideal for giving plants an extra boost between regular fertilization without causing soil nutrient build-up.
Modern silver watering can watering Peperomia plants
How To Choose A Houseplant Fertilizer
The most important aspect of feeding your houseplants is choosing a fertilizer, which means first understanding what NPK means. The most simple way to fertilize plants is to use a liquid fertilizer, which we will explore in more detail shortly. You should only ever use water that has been allowed to rise to room temperature to avoid shocking the plants. If watering with tap water, use a plant safe dechlorinator to remove chlorine and chloramine. Fertilizers are also available as soil amendments, biofertilizers, and slow release granules, so there are a few points to cover as we dig into how to feed plants. When it comes to fertilizers, NPK is king, as it tells you which fertilizer is right for your houseplant, so first, let's explore what those numbers on the plant label mean and how it changes indoor plant growth.
What Is NPK?
NPK stands for Nitrogen, Phosphorus, and Potassium. When selecting fertilizers for your houseplants, it's essential to understand the labels and what each component does for your plants. Fertilizer labels display an NPK ratio, such as 10-10-10. These numbers represent the percentage of Nitrogen (N), Phosphorus (P), and Potassium (K) in the fertilizer. Each of these nutrients plays a vital role in plant health, and can be used to treat plant nutrient deficiencies. Here's what NPK means and how it influences plant growth:
Nitrogen (N): Promotes healthy leaf and stem growth, and promoted lush green foliage. It's a key component of chlorophyll, essential for photosynthesis. Frequently used to increase foliage growth with concentrations like 20-10-10. Signs of a deficiency include yellowing leaves (chlorosis), stunted growth.
Phosphorus (P): Crucial for root development, energy transfer, and flowering. It aids in the formation of flowers, seeds, and fruit. Frequently used in high concentrations like 10-30-10 to promote flowering. Signs of a deficiency include poor root growth, delayed maturity, purplish discolouration in leaves.
Potassium (K): Important for overall plant health. It helps with water uptake, enzyme activation, plant vigor, stem strength, stress tolerance, and disease resistance. Deficiencies include brown leaf edges, weak stems, poor fruit and flower development.
Easiest Way To Learn NPK
NPK can be easily remembered by using the “Up, down, all around” rhyme. Nitrogen is the up, referring to the way it increases foliage and plant height. Phosphorus is the down, referring to the way it helps root growth. Potassium is the all around, referring to how it improves general plant growth both above and below soil.
Types of Fertilizer Ratios
Balanced Fertilizers: These have equal proportions of NPK, like 10-10-10. These are suitable for general houseplant care for most species.
Specialized Formulas: Target specific needs, such as high phosphorus 10-30-10 for flowering plants, or high nitrogen 20-10-10 for leafy growth. NPK shows us how different fertilizer ratios impact plant development, allowing us to cherry-pick desirable traits. By understanding what NPK does, you can achieve a specific goal, like adding more Nitrogen for foliage, or to choose species appropriate NPK ratios that would have been confusing before you learned what the numbers on fertilizer mean.
What Are Macronutrients In Fertilizer?
In addition to NPK, fertilizers may contain macronutrients. If you can't find this information on the label, contact the fertilizer manufacturer. Macronutrient deficiencies can cause serious visible issues, and are essential in smaller amounts for optimal plant health and growth. Here's why we give houseplants macronutrients:
Calcium (Ca): Strengthens cell walls and aids in root and leaf development.
Magnesium (Mg): Central component of chlorophyll; crucial for photosynthesis.
Iron (Fe): Important for enzyme functions and chlorophyll production.
Zinc (Zn), Manganese (Mn), Boron (B), Copper (Cu), Molybdenum (Mo): Vital for biochemical processes.
Sulfur (S): Integral for protein synthesis and chlorophyll formation.
Granular amendment
What Are Micronutrients In Fertilizer?
Micro nutrients and trace elements aren't often added to indoor plant fertilizers, and they are vital for plant health. When growing plants indoors, once the original supply of micronutrients within the potting soil has been used up, we are responsible for replenishing those nutrients before they cause deficiencies. Let's explore what each micronutrient does to our houseplants:
Silica: Enhances plant strength and resistance to pests and diseases.
Calcium: Strengthens cell walls, supports root and leaf development.
Magnesium: Essential for chlorophyll production and photosynthesis.
Sulphur: Important beneficial element for protein synthesis and chlorophyll formation.
Iron: Vital for enzyme functions and chlorophyll production.
Zinc: Supports various biochemical processes within the plant.
Manganese: Helps in photosynthesis and nutrient absorption.
Boron: Essential for cell wall formation and reproductive growth.
Copper: Plays a role in photosynthesis and enzyme activation.
Molybdenum: Important for nitrogen fixation and enzyme functions.
Granular amendment
Liquid Fertilizers For Houseplants
Liquid houseplant fertilizers are a popular choice because they are easy to apply and provide nutrients to plant roots directly, giving an immediate boost. Applying liquid plant food is simple, mix the fertilizer with water following the manufacturers directions. Liquid plant food is suitable for most houseplants, you can adjust the ratio of NPK by diluting it with more water. Avoid overfeeding, as it can cause nutrient burn. Follow the manufacturer's guidelines, leaving at least 2 weeks between feeds for most species. Observe plants after feeding and reduce the frequency of feeds at the first sign of stress. Always use room temperature dechlorinated water when fertilizing houseplants. Let's explore fertilizers:
Types of Liquid Fertilizers:
Keep all fertilizers away from cats, dogs and pets, as they can be toxic to them.
All-Purpose Fertilizers: These contain a balanced ratio of nutrients (e.g., 10-10-10) and are suitable for most houseplants.
Specialized Fertilizers: Formulated for specific plant needs, such as bloom boosters (high in phosphorus) or growth enhancers (high in nitrogen).
Organic Options: Derived from natural sources like seaweed, fish emulsion, or compost teas.
The Best Liquid Houseplant Fertilizer Concentrates:
Growth Technology Formulex Nutrient Solution NPK: 2.3-3.9-3.4
Type: Non-organic all-purpose fertilizer for balanced growth.
Recommendation: This brand is our personal favourite, as we've experienced great results using this product with our nursery plants. The ingredients are all bioavailable, so it's easy for the plant to access the nutrients. This is a complete feed that contains all micronutrients, macronutrients, and trace elements.Baby Bio Houseplant Food NPK: 10.6-4.4-1.7
Type: Non-organic all-purpose fertilizer which promotes strong foliage growth with high nitrogenType: Organic all-purpose fertilizer which promotes general growth
Miracle-Gro All Purpose Water Soluble Plant Food NPK: 24-8-16
Type: Non-organic all-purpose fertilizer which promotes foliage, flowering, and strong stem growthMiracle Gro All Purpose Concentrated Liquid Plant Food NPK: 7-3-5
Type: Organic all-purpose fertilizer which promotes foliage, flowering and all around growthPhostrogen All Purpose Plant Food NPK: 16-10-24
Type: Organic specialist potassium heavy all around fertilizer for strong stemsMiracle-Gro Performance Organics All Purpose Liquid Plant Food NPK: 4-1.5-4
Type: Organic all-purpose fertilizer for all around growthThe Natural Plant Food Company Tend House Plant Feed NPK: 4.1-0.56-9
Type: Organic all-purpose fertilizer for non-flowering plants with strong stem growthHouseplant Focus Balanced Liquid Concentrated Fertilizer NPK: 1.9-0.7-3.3
Type: Non-organic all-purpose fertilizer for non-flowering houseplants that provides strong stem growthEnvii Allgrow — Organic House Plant Food NPK: 6-2-4
Type: Organic all-purpose fertilizer for strong all round growth
The Best Ready To Use, Pre Diluted Houseplant Fertilizers:
Type: Non-organic all-purpose fertilizer for all round plant health
Miracle-Gro Drip & Feed All Purpose Plant Food
Type: Non-organic all-purpose drip feeder which promotes general plant healthMiracle-Gro Pour & Feed Liquid Plant Food
Type: Non-organic all-purpose fertilizer which promotes whole plant healthBaby Bio Houseplant Drip Feeders
Type: Non-organic drip feeder for hands off plant feeding with all round growth
Granular & Slow Release Houseplant Fertilizer
When you don't want to use liquid fertilizers, granular or slow release plant food can be a great option. Slow release plant food allows you to give your plants food less frequently without worrying about missing a feed. When applying granules, work them into the top few inches of soil, and water thoroughly after application with dechlorinated water that has risen to room temperature. For slow release fertilizers, follow the manufacturer's guidance. Keep a close watch on plants after fertilizing, if you have issues, put the plant in the sink and water the plant until it drains out of the bottom to help flush any built up fertilizer residue.
Keep all fertilizers away from cats, dogs and pets, as they can be toxic to them.
Miracle-Gro Indoor Plant Food Spikes NPK: 6-12-6
Type: Slow release spikes that go into the plant pot, which promotes flowering and general growthMiracle-Gro All Purpose Continuous Release Plant Food NPK: 3.9-9.1-1.2
Type: Slow release granular plant food which promotes floweringGro-Sure 6 Month Slow Release Plant Food NPK: 12-7-17
Type: Long term 6 month slow release food for stem and foliage growthMiracle-Gro Continuous Release All Purpose Plant Food NPK: 3-11.6-1.5
Type: Granular slow release food which promotes floweringGoulding Slow Release Fertilizer General Purpose Granular Plant Feed NPK: 14-6-12
Type: Continuous release granular fertilizer which promotes all round growth and floweringJobes Houseplant Food Spikes NPK: 13-4-5 Highly recommended
Type: Highly popular slow release spikes, which promotes foliage growth. Perfect for most houseplantsDoff Slow Release Multi Purpose Plant Food
Type: Granular continuous release plant food which promotes overall healthGro-Sure 6 Month Slow Release Plant Food NPK: 12-7-19
Type: Continuous release granular plant food which concentrates on foliage, stems and roots
Measuring granules
Biofertilizers For Houseplants
Biofertilizers are natural houseplant fertilizers that contain living microorganisms, which form symbiotic relationships with plant roots. These natural fertilizers enhance soil nutrients by converting atmospheric nitrogen into a form that plants can use, they solubilize phosphorus, and they improve soil health by increasing microbial activity. This symbiosis between houseplants and microorganisms provides essential nutrients for your houseplants, which in turn promote stronger roots, better foliage, and vibrant blooms indoors. Biofertilizers are an eco-friendly alternative to synthetic chemical fertilizers, and they're usually pet and child safe. Utilizing biofertilizers can lead to healthier, more resilient houseplants by stimulating growth with natural hormones and enzymes. Lets explore the most useful biofertilizers that are commercially available for houseplants, and what they can do for you.
Keep all fertilizers away from cats, dogs and pets, as they can be toxic to them.
Trichoderma:
Role: A plant growth-stimulating fungus that helps in nutrient uptake and disease resistance.
Use: Commonly mixed into soil to enhance root health. Trichoderma helps to protect against soil borne pathogens, as proven in this study.
Where To Buy Trichoderma: Tricho Protect, and TNC TricorrP5.
Arbuscular Mycorrhizae:
Role: Enhances nutrient and water absorption by forming a symbiotic relationship with plant roots.
Use: Improves nutrient uptake. Studies have shown it helps to increase tolerances to abiotic and biotic stressors, and increase growth rates when under stress.
Where To Buy Mycorrizal Fungi: TNC, Empathy Root Grow, Envii Root Well, Vitax Q4, Vitax Q4 Plus, RootMax, and Dynomyco.
Plant Growth-Promoting Rhizobacteria (PGPR):
Role: Includes various bacteria like Bacillus and Pseudomonas that promote plant growth and health.
Use: Applied to soil to stimulate growth. Several studies have shown it to stimulate root growth and to enhance plant health.
Where To Buy Rhizobacteria PGPR: Canna, and Biobizz.
Seaweed Extract:
Role: Provides a broad spectrum of nutrients, growth hormones, and stress-relieving compounds.
Use: Used as a liquid fertilizer or soil conditioner, enhancing plant vigor and resilience. There are studies that show seaweed can create a resilience to pest infestations. We always treat our nursery plants with seaweed after repotting or pruning, as it can help reduce stress, transplant shock, and it promotes good soil health. We think this really helps the plants to recover, and we highly recommend using it in your plant care routine.
Where To Buy Seaweed Extract: Maxicrop, Envii, Doff, Empathy, Empathy Ready Mixed, Alga-sol, Multi-Mite, and Vitax
Sapropel Extract:
Role: Derived from lake sediments, rich in organic matter and beneficial microorganisms.
Use: Improves soil structure, enhances nutrient content, and supports plant growth. Studies have reported positive effects on plant growth in some species.
Where To Buy Sapropel Extract: Ecoworm Sapropel Extract
Vermiculture Extract:
Role: Derived from worm castings, vermicompost extract is rich in organic matter and beneficial microorganisms.
Use: Enhances soil structure, nutrient content, and supports plant growth. Studies have shown that vermiculture extract can significantly improve plant growth and health.
Where To Buy Vermiculture Extract: Ecoworm Soil Extract
Kelp Seaweed
Organic Soil Amendments:
Compost: Rich in organic matter and nutrients, it enhances soil fertility. Compost can be sterilized to prevent pest infestations.
Worm Castings: Provides a balanced nutrient supply, improves growth and improves soil structure. Available as a soil additive and in a liquid form.
Leaf Mold: Adds organic matter and slowly releases nutrients as it breaks down. Find dead leaves under most mature trees.
Seaweed Extract: Supplies trace elements and growth hormones, enhancing plant health. Seaweed extract is our favourite amendment, except for humic & fulvic acids.
Chicken Manure: High in nitrogen, phosphorus, and potassium. Acts as a biofertilizer, adding microorganisms to soil. Manure enhances soil texture and water retention.
Farmyard Manure: Contains nitrogen, phosphorus, and potassium. Farm Manure adds microorganisms to the soil, improving soil texture, and promoting better aeration.
Fish, Blood & Bone Meal: Supplies nitrogen, phosphorus, and potassium. Fish & bone meal enhances soil fertility and texture, supporting healthy root development.
Wood Ash: Wood ash can neutralize acidic soils, making them more alkaline. Wood ash contains potassium, calcium, and trace minerals. Enhances soil water retention.
Bonemeal: Provides phosphorus, which is essential for roots and flowers. Bonemeal also provides calcium, which is important for cell wall strength and overall plant health.
Mineral-Based Soil Amendments:
Rock Phosphate: Provides slow-release phosphorus, essential for root and bloom development. Available as Vitax 1.25kg, Westland 1.5kg, and Miracle Gro 1.5kg.
Gypsum: Adds calcium and sulphur, which are vital for plant growth. Gypsum is a natural soil improver.
Volcanic Rock Dust: Contains a range of minerals, including basalt, which is rich in silica. Volcanic rock dust promotes microbial activity, stem strength and thicker leaves.
Sulphur: Natural soil amendment that adjusts pH and adds sulphur, which enhances nutrient availability, improve soil structure, and support healthy plant growth.
Dolomite Lime: Its primary uses are to adjust soil pH, making acidic soils more alkaline. Dolomite adds essential nutrients like calcium and magnesium to the soil.
Calcium Nitrate: Strengthens cell walls, improves plant structure and resistance to diseases. CaO promotes vigorous growth, as nitrogen is a critical component of chlorophyll.
Speciality Soil Amendments:
Biochar: While primarily used to improve soil structure and retain nutrients, biochar can enhance soil fertility indirectly by promoting beneficial microbial activity.
Humic Acid: Enhances nutrient uptake, improving soil health, plant growth and health. Humic acid is a component in our favourite fertilizer.
Fulvic Acid: Improves nutrient uptake, enhances soil structure, stimulates growth and increases microbial activity. Fulvic acid is a component in our favourite fertilizer.
Sapropel Extract: Biofertilizer rich in organic matter and beneficial microorganisms, sapropel extract enhances soil fertility and supports plant growth.
Soil Amendments For Houseplants That Fertilize
Amendments like compost, peat moss, perlite, and vermiculite improve soil structure, aeration, and water retention, ensuring that plant roots receive the right balance of air and moisture. They also enhance nutrient availability and support beneficial microbial activity, which helps plants absorb essential nutrients more efficiently. By enriching the soil, amendments promote vigorous root development, robust plant growth, and overall health, leading to more vibrant and thriving houseplants. Let's explore the most common soil amendments for indoor plants, where to buy them, and why they're useful.
Keep all fertilizers away from cats, dogs and pets, as they can be toxic to them.
Soil amendments
NPK Deficiencies:
Nitrogen (N):
Symptoms: Yellowing of older leaves, stunted growth, weak stems, reduced leaf size, pale leaves, overall plant growth slowdown.
Treatment: Apply a high-nitrogen fertilizer (e.g., 20-10-10) every 2–4 weeks during the growing season. Organic options are compost, manure, or fish emulsion.
Phosphorus (P):
Symptoms: Dark green leaves, purplish discolouration, poor root development, leaves may appear smaller, delay in flowering, leaves falling off prematurely.
Treatment: Use a high-phosphorus liquid fertilizer (e.g., 10-30-10) or organic bone meal mixed into soil. Ensure soil pH is between 6.0 and 7.0.
Potassium (K):
Symptoms: Brown leaf edges, weak stems, poor fruit and flower development, leaf curling, chlorosis (yellowing) between veins, reduced resistance to diseases.
Treatment: Apply a high-potassium fertilizer (e.g., 10-10-20) or potash, or use organic wood ash or kelp meal, sparingly. Ensure even distribution and water thoroughly.
Macronutrient Deficiencies:
Calcium (Ca):
Symptoms: Blossom end rot in fruits, distorted new leaves, weak stems, necrotic spots on leaves, leaf edges curling upwards, new growth stunted or deformed.
Treatment: Apply calcium nitrate, lime, or gypsum. Ensure consistent moisture levels to prevent calcium uptake issues. Mix lime or gypsum into the soil, or use calcium nitrate in your watering routine.
Magnesium (Mg):
Symptoms: Yellowing between leaf veins, leaf tips turning brown, premature leaf drop, reddish-purplish leaf tints, leaf margins remain green while the rest turns yellow.
Treatment: Use Epsom salts (magnesium sulfate) diluted in water. Dissolve 1 tablespoon of Epsom salts in a gallon of water and apply every 4–6 weeks.
Sulphur (S):
Symptoms: Yellowing of new leaves, stunted growth, thin stems, leaves becoming pale, entire plant displaying yellowish hue, delayed maturity.
Treatment: Use sulphur-containing fertilizers like ammonium sulfate. Add compost or manure to the soil. Apply sulphur fertilizers during the growing season as per package instructions.
Micronutrient Deficiencies:
Iron (Fe):
Symptoms: Yellowing of young leaves with green veins (interveinal chlorosis), slow growth, new shoots may appear weak, leaf tips and margins turning brown.
Treatment: Use iron chelate or iron sulfate. Ensure soil pH is between 5.5 and 6.5 for better iron uptake. Apply iron supplements to the soil or as a foliar spray.
Zinc (Zn):
Symptoms: Stunted growth, small leaves, interveinal chlorosis on new leaves, crinkled leaf appearance, shortening of the distance between leaves, delayed leaf opening.
Treatment: Apply zinc sulfate or a micronutrient mix containing zinc. Use compost or manure. Apply zinc sulfate to the soil or as a foliar spray.
Manganese (Mn):
Symptoms: Interveinal chlorosis on leaves, brown spots, reduced growth, grey speckling, necrosis (death of tissue) at leaf tips and edges, poor root development.
Treatment: Use manganese sulfate mixed into soil or a micronutrient foliar spray containing manganese. Maintain soil pH between 6.0 and 7.0.
Boron (B):
Symptoms: Stunted growth, thickened stems, root tips dying, brittle young leaves, leaf edges may turn yellow and die, flower and fruit abnormalities, hollow stems.
Treatment: Apply borax sparingly or use a micronutrient mix containing boron. Dissolve 1/2 teaspoon of borax in 1 gallon (4.55 l) of water and apply to the soil.
Copper (Cu):
Symptoms: Yellowing of leaves, wilting, stunted growth, dieback of stems and twigs, dark green leaves with blue-green tinge, leaf edges curling inwards, reduced flowering.
Treatment: Use copper sulfate or a micronutrient mix containing copper. Apply copper supplements to the soil or as a foliar spray.
Molybdenum (Mo):
Symptoms: General yellowing of older leaves, twisted leaves, pale green or yellow spots, marginal scorching of leaves, stunted plant growth, poor flowering.
Treatment: Apply sodium molybdate or a micronutrient mix containing molybdenum. Use molybdenum supplements sparingly, as plants require very small amounts.
Other Essential Nutrient Deficiencies:
Silica:
Symptoms: Weak stems, increased susceptibility to pests and diseases, lodging (falling over) of plants, brittle leaves and stems, slower growth.
Treatment: Use silica supplements or products containing silicon dioxide. Follow the manufacturer's instructions for dosing and application.
Chlorine (Cl):
Symptoms: Poor root development, wilting, reduced growth, leaf bronzing, leaf tip and edge burn, yellowing and browning of leaves.
Treatment: Typically not required, as chlorine is usually sufficient in tap water. If using dechlorinator, decrease the frequency of use until symptoms disappear.
Nickel (Ni):
Symptoms: Poor seed germination, stunted growth, leaf deformities, necrotic spots on leaves, yellowing and browning of leaf margins, poor nitrogen metabolism.
Treatment: Apply a micronutrient supplement containing nickel. Use nickel supplements sparingly, as plants require very small amounts.
How To Spot Nutrient Deficiencies In Indoor Plants
Yellowing leaves
Brown crispy leaf tips
Brown crispy leaf
Weak, snapped stem
Chlorosis between veins
Yellowing of older leaves
Signs Of Nutrient Deficiencies In Houseplants
Sometimes, no matter how good potting soil or fertilizers are, plants can get nutrient deficiencies that show up as visible issues with plant health. When plants have issues, you may wonder what caused your plant to get sick. Let's explore the symptoms of deficiencies to help you diagnose what nutrient your plant is lacking, and how to treat it:
Nutrient burn on an Alocasia Silver Dragon
How To Fix Nutrient Burns In Houseplants
If you've ever had brown crispy leaf tips, it's likely that you've experienced nutrient burn. This is a condition that occurs when plants receive an excessive amount of nutrients. Over-fertilization leads to a build-up of mineral salts and nitrogen in the soil, which can damage the plant's roots and hinder its ability to absorb water, slowly starving it to death. Nutrient burn is often visible as yellowing or browning of leaf tips and edges, like pictured, which can spread if ignored. The symptoms of nutrient burn typically start at the tips of the leaves and move inward. In severe cases, the leaves may become crispy and curl, much like the Alocasia in the photo.
Preventing nutrient burn involves careful monitoring of nutrient levels and following recommended fertilizer guidelines. It's also important to ensure proper watering practices, as adequate water helps flush excess salts from the soil. If nutrient burn occurs, flushing the soil with plain water can help leach out the excess nutrients and restore a balance that promotes healthy plant growth. Reduce the frequency of feeds for your plant, and monitor for any other signs of stress.
How To Flush Houseplant Soil:
To flush nutrients out of plant soil, water the plant thoroughly by allowing excess water to drain out from the bottom of the pot. Repeat this process several times, letting the water run through the soil, to remove built-up salts and excess nutrients. Ensure the pot has good drainage to prevent root rot.
Flood & Drain Watering Technique
When watering houseplants, over time, mineral salts can build up in the soil, giving your plants too many nutrients. One of the best ways to combat this invisible issue is to use the flood and drain watering technique, also known as ebb and flow. This is a method of watering houseplants where the plant roots are periodically flooded with nutrient-rich water and then allowed to drain, then dry out.
This is beneficial for houseplants because it mimics natural growing conditions where plants experience periods of rain, followed by drainage, then dry spells, which prevent issues like root rot. When the water drains away, it carries away excess salts and nutrients that can accumulate over time, harming your plant. This flushing action prevents nutrient lockout, where plants are unable to absorb nutrients due to an imbalance in the soil. Flood and drain watering ensures that plants have access to fresh nutrients each time the system floods, leading to more consistent and vigorous growth. We use this technique ourselves when we notice salt build-ups in the soil, or burnt leaf tips, which are a sign of nutrient burn.
Fishbone Cactus being watered
Safety Around Pets
Liquid fertilizers can be beneficial for plant growth, but they can pose risks to pets if not used and stored properly. Always read the label on the fertilizer container for any specific warnings or instructions regarding pet safety. Some fertilizers may contain ingredients that are particularly harmful to pets. Keep liquid fertilizers in a secure, pet-proof location. Make sure the container is tightly sealed and stored out of reach of curious pets. When applying liquid fertilizers, ensure that pets are kept away from the treated area until the fertilizer has fully absorbed into the soil and dried. This reduces the risk of ingestion or skin contact. If you spill any liquid fertilizer, clean it up right away to prevent pets from coming into contact with it, or drinking it. After using liquid fertilizers, watch your pets for any signs of distress or illness. Symptoms of fertilizer poisoning can include vomiting, diarrhoea, drooling, lethargy, and seizures. If you suspect your pet has ingested fertilizer, contact your veterinarian immediately.
Other Types of Fertilizers to Keep Away from Pets
In addition to liquid fertilizers, there are other types of fertilizers that should be kept away from pets. These can be ingested by pets if they eat the fertilizers directly or if they lick their paws after walking on treated soil. Keep slow release granules in a sealed container stored away from pets. While often perceived as safer, organic fertilizers made from bone meal, blood meal, fish emulsion, or manure can still be harmful if ingested by pets.
Dog drinking from a watering can
Edited & Fact Checked By: The Houseplant Shop
Article Published: 12th December 2024
About The Houseplant Shop:
Independent Houseplant Nursery
Horticultural Specialists
Managing Over 250 Houseplant Species Onsite
Over 15 Years Of Experience With Horticulture
As head of horticulture, Sarah manages the care and propagation of over 250 plant species at a commercial houseplant nursery. With over 15 years of experience in horticulture, specializing in houseplants, Sarah has extensive expertise in plant biology, soil science, and integrated pest management. She continually reviews and integrates the latest research into her plant care guides. Dedicated to educating others, Sarah has spent years diagnosing houseplant care issues and sharing her real-world experience. Her commitment to scientific accuracy and helping people diagnose plant health issues has established her as a trusted authority and expert in the field.
The Houseplant Shop is a dedicated houseplant nursery, growing all of their own stock from their botanical library of over 250 houseplant species. The nursery staff are horticultural experts who have dedicated their lives to cultivating and nurturing over 250 different species of houseplants, focusing on Aroids, tropical plants, and NOID collectables. All their plants are grown in house in Britain to be more environmentally friendly. The nursery is proud to have been featured by the Royal Horticultural Society (RHS) as a 100% peat free nursery.
Recommended Further Reading:
People also looked at: Watering, and Self Watering Moss Poles, and A-Z Encyclopedia of Houseplants.
How We Reviewed This Article:
Our horticultural experts continually monitor the houseplant space, and we update our articles when new information becomes available. We are committed to providing current and reliable information. If you have some information that you think would be helpful in this article, we'd love to hear from you. Our team works hard to revise articles for factual accuracy, and we regularly update our pages with new information, techniques, tips, images, trade secrets, and real world experience from the team here at the houseplant nursery. You can find a list of the article updates below.
Written By: Sarah Brooks, Head of Horticulture
Article Received: 5th December 2024
Copyright: The Houseplant Shop (https://thehouseplant.shop)
The use, distribution, or reproduction is permitted, provided the original copyright owner is credited and that the original publication on this website is cited with a direct link to the article, only with these terms. Any other use is not permitted.
List of Article Updates:
20th December 2024: Minor UI updates
Author Bio:
Author: Sarah Brooks,
Head of Horticulture at The Houseplant Shop