Thank you for the detailed reply. I improved it: added clay balls on the top around plants- I figured that light had been coming inside, which should be avoided- right? I added another lamp and now every plant, even capricious dill are feeling good and growing. Now I have 2 bunches of kale, 2 plants of mint, 1 bunch of dill and the rest are green onions.

I just rinse the roots once a week, since mold appears sometimes.. (On the onion usually).

As for the pH meter- I bought one, but used one buffer powder incorrectly.

I have 4.0 pH powder left- can I calibrate the meter with it in distilled water?

Thank you again)

Natalia

Yes it's good you patched up the light leaks.

When rinsing the roots, I'd suggest utilizing 3% hydrogen peroxide when rinsing your roots. This can help kill off any additional bacterial problems. Lots of hydro shops will carry this low percentage peroxide but if you can't find it you can dilute a stronger peroxide down to 3%. Also if you notice any rotted roots carefully trim them out.

Unfortunately besides the 4.0 pH powder you'll also need a 7.0 pH solution to do a 2-point calibration. There should be instructions that came with your specific pen, If you don't have the instructions, there are lots of good resources if you simply Google "calibrating ph pen"

Unfortunately I don't have a writeup on calibrating pens right now to direct you to, however that sounds like something I need to do!

Thank you for all advice! You are very helpful!)

My pleasure!