By its very nature, the ZZ plant is a slow grower. To the untrained eye, it can look and feel like your ZZ plant isn’t growing. Fertilizer doesn’t make it grow faster. It supports growth.
To reach full maturity, it can take up to five years. How big your ZZ plant gets in that time frame is somewhat related to the fertilizer you give it.
Fertilizer for plants is not the same as food. You can grow a ZZ plant just fine with only the essentials that plants need to survive. Water, warmth, air, and nutrients. The last part of the nutrients is what makes the magic happen. The fertilizer is the vitamins that supports the plants growth rate, and its metabolism.
Nutrients are like vitamins for plants and that’s what fertilizers are the equivalent to. Supplements. Not food. Plants make their own food through photosynthesis.
Given the right type of fertilizer, dosage, and frequency, you may not need to wait years to grow a gorgeous focal point of a houseplant. The critical things to get right are the type of fertilizer to use and the frequency of which to feed it to your ZZ plant.
Get things wrong with the fertilizer, such as over-feeding it, or using the wrong type of fertilizer, it can do the plant more harm than good!
The Different Types of Fertilizers and Which is Best for the ZZ Plant
Plant fertilizers come in many varieties. Synthetic (chemical) natural (organic), granular (slow-release) and in liquid form.
Chemical fertilizers are manufactured with precision, giving exact nutrients in a bottle, capsule or pellet, ready to be fed directly into the soil for the ZZ plant to feed on.
Organic fertilizers are made from compost. You can control what you put in a compost pile, but it takes a lab analysis to know the exact nutrients the compost has.
To use compost, you have to mix it into the potting mix at a ratio of 1 part compost to 3 parts ordinary potting mix, plus vermiculite or perlite to improve drainage. What you can’t do with compost is layer it onto the top soil of a ZZ plant as that would create a moisture trap beneath the soil, likely leading to root rot or fungal growth that can kill a ZZ plant.
Knowing that, the safer type of fertilizer to feed a ZZ plant is a synthetic fertilizer. Then you have to decide on how it gets used.
Granular / Slow-Release Fertilizer
Granular fertilizers are always going to be slow-release, because it has to be broken down naturally in the soil before the plant can use it. For that reason, granular fertilizers will always be used up slower by plants than they would with a liquid fertilizer.
Slow-release fertilizers are usually pellets or stakes that are placed in the soil then slowly release nutrients as the pellet decays – or in the case of stakes, each time you water the plant, some nutrients are released. These are mostly favored for outdoor plants.
Liquid fertilizers act instantly. The plant and soil don’t have to wait for anything to break down. All the macronutrients and micronutrients are already activated in the solution. This is the type to use with the ZZ plant because you can control the frequency of fertilizing better.
As the ZZ plant goes dormant in the winter months, you can stop feeding fertilizer around August/September. With a granular product, additional minerals could be released when the plant has no need for it resulting in over-fertilization.
The Right NPK Ratio to Use
If you think adding fertilizer will make your ZZ plant flower, stop! That’s not going to work. Although ZZ plants can flower, they rarely do.
For that reason, there’s no need to adapt the fertilizer composition to encourage blooming. Fertilizers that are designed to promote flowering in plants have the amount of phosphorous bumped up.
The ZZ plant doesn’t have any specific nutrient requirements. What matters most is that everything it gets, it gets in equal amounts. That means an equal NPK ratio. The term used for this type of supplemental plant food is a balanced fertilizer. All that means is that all the numbers on the label are the same.
These are usually a 10-10-10 or 20-20-20 fertilizer. They are all-rounders that can be used with all houseplants, and leafy greens that don’t flower. They are available in liquid or pellet form.
Feed the ZZ plant a balanced liquid fertilizer so that it can get the nutrients instantly.
The Micro and Macro Nutrients to Look for
All fertilizers have 3 main components. Nitrogen (N), phosphorous (P), and potassium (K). The letters NPK on the labels of fertilizers use the chemical symbols for each of those elements.
These are the macro nutrients that all plants need, so every type of fertilizer will have each, just in different ratios.
There is more that differentiates plant fertilizers than the NPK ratio though. There are additional micro nutrients in each. The micro nutrients are minimal as plants don’t need much of them.
The beneficial micro nutrients for the ZZ plant include boron, calcium, copper, iron, manganese, molybdenum, sulfur, and zinc. The more traces of those ingredients the fertilizer has, the better it’ll perform for your ZZ plant.
Once you have that nailed, next is to get the frequency of feeding right. To understand that, it’s helpful to know the natural growth rate of the ZZ plant. It goes dormant in the winter, which is why slow-release fertilizers are ruled out, unless you only use it at the start of the growing season.
How to Use a Liquid Fertilizer for the ZZ plant
A liquid fertilizer is supplied as a concentrate that ought to be diluted so as not to burn your plants delicate roots. The term 10-10-10 means that has 10% of each macro nutrient, the rest of the concentrate is a filler with trace amounts of micro nutrients.
All liquid fertilizers should be diluted to half strength at least. For stronger fertilizers, such as 20-20-20, dilute to a quarter of its strength before applying to plants.
The best way to use a liquid fertilizer is to add it to the soil the day after it has been watered thoroughly. This is an additional protection against fertilizer burn. It’s ill-advised to add fertilizer to dry soil.
The Right Fertilizer Frequency
Throughout the year, the frequency that a fertilizer is used should be varied. ZZ plants don’t need much fertilizer so it’s easy to over do it.
As the fertilizer is used to support the plant’s growth, only add it when the plant should be actively growing. That’s in the spring through summer, and stopping feeding it in the winter.
Starting in the spring, the plant will be getting ready for growth. Go slow at this stage and apply a feed around mid-March, then again a month later. This will help give it a jump start when the brighter days come in around April.
From mid spring going into the summer, the frequency can be increased to bi-weekly or monthly, depending on how much of a risk you want to take. Bi-weekly is riskier as too much fertilizer can burn the roots and lead to a ZZ plant turning yellow.
Also note that the more fertilizer you use, the sooner the soil mix will need replaced because of the excess salt accumulation.
Approaching the end of the fall is when to slow the frequency of fertilizer use to let the plant use as much of the nutrients in the soil prior to it going dormant in the winter when the shorter days are no good for it. Around August, if you were feeding at a frequency of bi-weekly, cut it back to monthly and cease using fertilizer in the fall.
What to Do if Your ZZ Plant has been Over Fertilized
A sort of advantage to the fast-acting nature of liquid fertilizer is that when too much is added, the signs show fast.
Signs of an over fertilized ZZ plant are when the lower leaves wilt, leaves turn yellow, brown leaf tips emerge, and if left untreated, the roots can burn to the extent they turn brown or black and stop performing leading to whole plant defoliation.
These signs show within a day to three days after applying fertilizer. The way to fix fertilizer burn on plants is to drain it from the soil mix by flushing the soil with water thoroughly, then allowing ample time to dry – preferably in bright sunlight before adding any water again.
For a severely over fertilized plant, a white crust can form on the top soil. In those instances, the better solution is to repot the ZZ plant in a fresh potting mix and start again, this time being careful with the dosage (following dilution recommendations) and be more mindful of the frequency of fertilizing.
Applying more fertilizer before the plant has used what’s already there in the potting mix is what leads to an over abundance of fertilizer that causes problems.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.