Is there a recommended amount of diluted fertiliser that should be used per plant? Once I've diluted fertiliser (e.g. Tomorite) into water, I never really know how much of that water each plant should receive.

For example, I usually pour a 9-litre watering can with diluted Tomorite onto around 8 tomato plants in containers. I'd use the same amount for maybe around 15 flowering plants in containers. (The soil is already most beforehand.)

In other words, around 1L per tomato plant but a bit less for others. Is this about right?


  • 1
    Every fertilizer has a recommended dosage that is on the package. What is recommended for your fertilizer?
    – kevinskio
    Commented May 1, 2022 at 22:52

2 Answers 2


As long as you don't overwater your plant (with the diluted fertilizer), and you use the correct amount of fertilizer per amount of water—and your plant could use the fertilizer—you should be fine in giving it however much you want, in one fertilization. By implication, and my observations in doing it with a number of fertilizers, that seems to be what is expected. I've never seen anyone say differently. So the direct answer is no; there isn't a recommended amount, as far as I've seen.

Tomorite instructions here say to mix 20ml of Tomorite in 4.5 liters of water. You'll see that sort of thing on fertilizer packages; you won't see how much of the already-combined fertilizer-water to pour into the soil. You will likely see how often to apply it (but be careful there, as recommendations aren't always perfect, particularly in that they don't say how many applications in a row are safe, and it's not always safe to do it indefinitely).

Indoor plants generally require less fertilizer per amount of water. I'm guessing the recommendation above was for outdoor plants.

Anyway, how much water to give your plants depends on how big they are (the more leaves they have, the more water they'll use; even if you prune off leaves, they'll use less water), how big the containers are, and stuff like that. If your plants are large, in good-sized containers, the amount you're using sounds okay. If they're seedlings that's way too much.

It's generally best to fertilize when you water, to avoid overwatering, unless you do foliar sprays.


Teaspoon to 44 gallons. The usual dilution is a level tablespoonful in a gallon of water, or a pound in 44 gallons of water.

The number of applications varies with the crop, long-season ones requiring more. About one spraying every three weeks is usually recommended. I forgot myself, asked the wife 😅

  • I think you may want to recheck your numbers - as it’s written, they don’t match up.
    – Stephie
    Commented May 4, 2022 at 20:38

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