Al B. Fuct
once had a dog named
Yes, it's very easy to overwater rockwool. You SHOULD worry.
Rockwool is highly absorbent and cannot be flooded frequently. Saturating rockwool drives all the air out which is required for root formation. While you can use rockwool slabs or pots of rockwool floc as the main growing medium, depending on the volume of the rockwool used, it can only be flooded 1x/day. I used 175mm pots stuffed only with RW floc for years.
When watering rockwool used as the main growing medium, you should allow the plant to remove about half the water weight from the RW before flooding again. If the RW is saturated, it will not take in more water, so flooding RW frequently is not only not good, it's big-time bad. The water in the medium will lose its dissolved O2 before the plant can take up the water, encouraging anaerobic pathogens.
The name of the game in hydroponics productivity is oxygen to the roots. If you can flood the roots more frequently with oxygenated nute solution, you can get more O2 to the roots.
RW does not lend itself well to frequent flooding, but because it holds a lot of moisture, is very good for starting clones.
Pellets hold almost no water and have large air spaces between them. You can flood roots which have knit down into pellets several times per lights-on.
For theses reasons, many people start clones in RW cubes but then plant them in pellets in flood systems once the roots are grown out of the cube bottom.
However, roots in cubes can not tolerate being watered as often as roots in pellets. To make the transition, newly rooted RW cubes should be nested in the pellets so the cube is about 1/2" ABOVE the flood level. The roots will seek down into the damp pellets below in a few days. If it makes you feel better, you can handwater the pellets AROUND the cube (not the cube) for the first week after a cube has been nested in the pellets- but they will find the pellets on their own if they are being flooded frequently enough.
The pellets should be flooded about 5x per lights-on. If the flood level is allowed to contact the cube, it will be saturated and you may get overwatering symptoms. Once the plant has been put in the pellets, the RW is extraneous.
Once the roots are knitted into the pellets, they'll do fine with 5x floods/lights-on or even more if the plants are large and vigorous.
I'd allow about 5L of reservoir capacity for each plant.
Not sure what you're up to with that thin layer of pellets in half your tray.
It can be done, as I've just described- you just have to assure that the cube isn't saturated when making the transition into pellets.
Since you haven't told me anything about your setup,
I'm going to look into my crystal ball... you're flowering with fluoros, right? 7 weeks of veg & bloom Did you start from seed or clones? How long did you veg? How long have they been flowering?Sorry, I'm not an outdoor guy. Can't help you.
Draw in the coolest air you can get. Dump it where it can't be sucked right back into the grow.
If you can't get air at ~25C to draw into your op, you will need aircon.
Outdoor plants show heat stress if they're exposed to high temps, too. Effects include leggy growth, runny or bolting buds, etc. If it's hot enough and dry enough for long enough, cannabis plants will cark it. Cannabis is a very thirsty plant.
Your yield and density would have been lots better at 24-26C. THC begins to break down into non-psychoactive components at 29C, so high temps can be robbing you of potency even before you harvest.
I use 175mm dia x 175mm tall pots which are about 4L in volume.
You're on your own with Hempys. They keep roots submerged without oxygenation. That's a recipe for root rot. I'm glad you're comfortable with them. Rotsaruck.
Nope, that won't work. Gonna have to improve the ventilation and get that cooltube. If you have 25C air to draw in, when you have everything right, it'll stay at 25C or very close to it.
) I did that so my feed water would not run through so fast, seems to work, I have a lot less runoff. Do you think that I am robbing my plants of oxygen or is the 80% hydroton in the bottom good? I'm working on a 'perfect' environment, and certainly don't want to f up my grow with something like that?!
(That I don't have)