I tripped across water storing crystals by accident and could find no information about planting plants straight in the crystals. So I potted two orchids in them today and we’ll see how they do?
You can purchase colored and different sized crystals to use in floral arrangements.
Probably one tablespoon per plant is more than enough. Next time I use them I’ll mix them into the soil or container dry, add the plant, then add the water. It was pretty messy soaking them then trying to get them in the containers and around the roots.
Several companies make them not all use the same formula. Some are polyacrylamide hydrogels (dissolve, last 3-4 months), some are cross-linked (not dissolvable, last 3-5 years) both seem to use potassium. The crystals are in the cross-linked group.
Exposure to heat and light breaks the crystals down, so if you have plants in sunny locations, bury the crystals in the soil.
The best results I’ve seen reported by gardeners is to put the crystals and some dry medium ( pebbles, styrofoam etc ), and soil at the bottom of the pot and soil above.
It turned out not to be a good idea for house plants.
The crystals didn’t work out for house plants. They had to be watered much more often rather than less. The water crystals took up the water but weren’t so good about giving the water back up. They were especially bad with the orchards potted in mulch. They formed clumps blocking the roots from getting air.