Hello Professor,
I started a bunch of seeds in rockwool and transferred them to red party cups filled with perlite as soon as they sprouted. I am feeding them with a weak fertilizer and have them under some cool white fluorescent lights. The plants are getting droopy and yellow and refuse to grow. Do you know what’s wrong?
Ash
Hey Ash,
One-hundred percent perlite is a poor choice of growth medium. The young plants are not getting the proper levels of water and oxygen. You need to immediately transfer them to a soil or hydroponic system to save them. Perlite makes a wonderful amendment to soil mixes and I use it every time, but as a standalone medium it pretty much sucks. The one exception to this would be a small hydroponic system, but even then the light weight of the perlite creates some stability problems.
Act quickly and you can save your crop!
Professor Lee
