I have half a dozen large pots (24"+) on my balcony which I've used for a couple of years to grow tomatoes, peppers and herbs. Last year I rotated several pots from tomato to peppers and vice versa, and top-dressed all with LARGE bag of fresh potting soil -- herbs did well, so did green onions, but peppers and tomatoes suffered. What do I need to add to the soil to make it healthy? Does to be more than all-purpose fertilizer -- like calcium or something? Iron? It's not feasible for me to replace it, I'm on the third-floor and I'm o lder (i.e., weaker!).

  • two years is probably more than enough to reuse the same soil, particularly if you are growing food plants like tomatoes... You need to find a way to clear out the pots, have new potting soil delivered, wash and sterilize the pots you've got, then fill with new potting soil. Soil in pots which has previously grown produce may be contaminated with pathogens, which is why you need to replace it perodically. Or use grow bags instead.
    – Bamboo
    Feb 13, 2018 at 12:13

2 Answers 2


You rotated tomato and peppers, which are two species of the same family, so it is not a real rotation, both plants used the same nutrients.

On the other hand, rotating on pots it is not so convenient, so yes, you need a all-purpose fertilizer. Usually it is enough, without requiring specialized fertilizers. You wrote that you put also new soil, which is also good for extra nutrients.

But from time to time, it is good to change the soil (repot or just changing the soil). You need it every few years, so you should ask some help. Maybe some deliver service will bring directly to your door (at 3rd floor).

If after fertilizing the problem persists, you should ask again, with photo of the leaves, so that we can help finding if you need more specialized fertilizer).


The point of crop rotation is to reduce the risk of persistent pests and soil diseases which is much less since you're on the third floor presumably growing on a balcony.

About 90% off the plant's bulk comes from the air with the rest from the soil. When you added the potting mix to the surface you only added the small amount of fertilizers that come with the potting mix which meant that most of your soil was deficient of both macro and micro nutrients.

So you need to add a general purpose fertiliser to restore what was lost, and add some micronutrients which may not be in the general purpose fertiliser. Sea weed based fertilizers usually have these micronutrients. You can also try the latter as a foliar spray for quick remediation.

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