Fertilizing Succulents and Cacti

Fertilizing plants seems kind of scary to new growers, but in truth, it’s not hard at all. For succulents and cacti it’s practically optional!

Everyone has their own advice on how to fertilize plants, but here is what we do at Planet Desert – and the results speak for themselves!

What Kind of Fertilizer Do You Need for Succulents?

 Just about all plants need the same few primary ingredients in their fertilizer:

  • Nitrogen (N)
  • Phosphorous (P)
  • Potassium (K)

Usually, fertilizers are labeled as a ratio of the three – N:P:K – so you can see at a glance the proportion of each element.

Here at Planet Desert, we use 20-20-20 fertilizer. Note that the ratio of the elements are even (1-1-1), so fertilizers labeled as 10-10-10 or 5-5-5 are in fact the same proportion, they’re just more diluted.

This 1-1-1 ratio is the most common fertilizer type. It’s best geared towards vegetative growth – making more leaves and stem/trunk. Other ratios of fertilizer are used to encourage plants to flower or to help them in their seedling stages.

Some people say that cacti don’t need as much nitrogen or phosphorous. We haven’t found that to be true. Having tested the different types of fertilizer, the regular 1-1-1 mix works best… and we have a pretty big sample size.

Of course, plants can’t survive on just nitrogen, phosphorous, and potassium. They need about 10 or so other elements to grow healthily, but they only need very tiny amounts. A lot of the time, these are already present in the soil, but since succulents and cacti tend to grow in less soil and more grit, it’s good to supplement them with micronutrients.

You can buy fertilizer that includes micronutrients in it or dose them separately. Plants don’t need micronutrients as often as they need fertilizer, but for convenience’s sake, we just do both at the same time.

Bonus Fertilizing Tip: Induce Cactus Flowering

One of the secrets we’ve learned over many years of running a nursery is how to get cacti to bloom almost on-demand!

This is an especially useful technique because some species of cactus are really difficult to tell apart without seeing their flowers. Compound that with the fact that many cacti can go years without flowering, which could postpone a positive ID forever.

The secret to making cacti flower is to add some dissolved ammonium sulfate to the water (or dissolve the powder into the water directly). That’s a specialty fertilizer which isn’t often sold at garden shops, but can be bought online fairly easily.

The ammonium sulfate should be applied in early spring as most cacti are coming out of their dormant winter phase. That’s typically when cacti are considering flowering anyway, so it gives them a little head start.

You don’t need a lot of ammonium sulfate to do the trick, so one bag should last years!

How Often to Fertilize Succulents

Succulents and cacti are adapted to live in soils that are poor in nutrients. That’s one of the reasons they tend to grow slower than other plants.

While it is very possible to go a year or more without fertilizing, you can speed up succulent and cacti growth a little bit by fertilizing them more often. In our plant nurseries here at Planet Desert, we mix in a small amount fertilizer every time we water.

That might not be the best strategy for you, though. It works for us because we have a massive number of plants and need to grow them year-round.

Generally speaking, it’s good practice to fertilize your succulents a handful of times a year. You should make an effort fertilize them at the beginning and throughout their active growing season (the opposite of their dormant season).

How Much To Fertilize Succulents

Since you usually just buy general-purpose fertilizer for your succulents, you’ll have to adjust the dosage to meet the needs of your succulents and cacti. Since they need less fertilizer than other plants, you’ll have to dilute it significantly.

Since we fertilize every time we water, we use very small amounts of fertilizer – about 150 ppm (parts per million). That’s roughly 1 lb of fertilizer in every thousand gallons of water, which is really not a lot of fertilizer.

It’d be very difficult to scale this down for a home grower who might only use a gallon or two of water for all their plants. You’d need an eye dropper to get the proportion right!

That’s why we recommend just diluting your fertilizer to 1/3 or 1/4 the recommended dose when you apply it.

Be careful not to use a high concentration of fertilize or you run the risk of harming your plants. Fertilizer that isn’t sufficiently diluted is somewhat caustic and can cause fertilizer burn, which will damage or kill roots.

Fertilizer can also change the pH of water in high concentrations. The ideal pH for most succulents and cacti is around 6.5. When properly diluted, fertilizer shouldn’t significantly impact your soil or water pH.

Fertilizing Succulents and Cacti Shouldn’t Be Hard

Fat plants aren’t picky. They’re forgiving of mistakes and great for beginners. Most succulents and cacti won’t be affected if you don’t fertilize them for months or even years, so if you’re not confident in your abilities yet, you can wait.

When you’re ready to jump in and give your plants a little extra love, follow our tips above! Do you have any fertilizing techniques you’d like to share? Let us know in the comments below!


  • Ryan Lothrop

    What is the ratio of water to ammonium sulfate you mix to encourage flowering? I want to make sure I don’t over do it. Thanks.

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