I don't think you want sand, but soil isn't a great idea as it should really be a soil-less mix.

It would not be too late to CAREFULLY take them out and re-plant them in a soil-less mix, with just a little of your mixture added in.

Do you have holes in the bottoms of the containers? Perhaps you could raise them up on bricks or blocks of wood so that they can drain better.

Good luck!
Linda

Thanks for the quick response here, Linda.
What's wrong with soil? What's a good soil less mixture? Compost, coconut coir, worm castings, perlite?
There are a good amount of holes, but I drilled some more anyway. The system itself shouldn't be the problem. One bucket has a bunch of holes for drainage and it sits in another bucket that has river rocks in the bottom and two holes 3 inches from the bottom to allow for drainage...

The problem with soil is that it compacts and doesn't drain. You might want to check out SIP buckets, a two-bucket system where you have a wick to suck up water from the lower bucket. You would still need a soil-less mix though.

Usually, people use peat moss or coir, perlite, vermiculite, and just a little compost/worm castings. I usually buy Pro-mix.

Linda

Oh wow I really should have done the sip water system. You're great, Linda. Thanks!

I dont believe in using sand in potting or in the garden. It has to be at least 35% if you want it to help drainage. Then it is too heavy and can make the soil compacted.

Perlite does a better job in container. But Adding things like peat moss, vermiculite is defeating the purpose of the use of perlite.

I would suggest that you look into 5-1-1 mix. That is what I am using in all my potted peppers and tomatoes ( close to 25 pots)