Vacation watering question

[roperman]

I'm going to be away from my grow tent for a week. I bought a programmable drip timer and all is good, I think I won't have any watering problems. The thing I'm worried about is too much humidity.

I have two 5 gallon pots with coco / perlite. It usually takes about 5 quarts to water, with about one quart draining out.

But I don't want water to drain out the bottom while I'm gone (I wouldn't want my catch to overflow), so I have to adjust and guess what would be a good dose. The timer has limited options. It can only water every so often, up to 90 seconds pump time. I figured that I could go with 1/2 gallon of water per day, per plant. I programmed the pump to pump for 90 seconds every 4 hours.

This means that the pots will never dry out and I'll be pumping one gallon a day into the tent. That's a lot of water that will cause high humidity. I have a fan that is exhausting air out of the top of the tent, so there will be air exchange. I'm already seeing some white spots on the outside of the cloth pots which makes me think this daily or every other day watering may be too much.

Any thoughts? Can I reduce the volume of water to 1/2 gallon per day safely? That would be 1 quart of water per plant per day.

Plants are in flower. I'm going to mix up a highly diluted nute batch so I don't burn the plants, like 1/4 the amount from the GH schedule (1/2 of what Nebula's chart says).

Thanks in advance for any advice you can throw my way.

(BTW, this is the drip timer I ordered: https://www.amazon.com/gp/product/B0743F4532 )

[9fingerleafs]

It all sounds great. I don’t think you’ll have any problems with humidity and the amount of water makes sense. One or two quarts a day. Maybe run the system a couple of days before leaving just to check everything works right. And the white spots on your pots it’s just water that dries out leaving behind minerals. Don’t worry about it. Just remove with water before reusing the pot

[Campesino]

Do you water daily at the amounts listed? That is both plants or each?
I have 7 gallons bags with coco perlite and I water everyday to drain off. I think your quantity is too high.
i give my plants about 1quart to 1.5quart each daily. That produces decent run-off. If I gave 1/2 gallon I would quickly overflow my catch. I think I could put about one quart in everyday at this point with minimal drain. My RH is in the 40s in the tent. RH will make a difference!

[Campesino]

Let me clarify. RH will affect how much water you can use without drain. If your RH is high then you need even less water. Based on the little I know about your set up and my experience with daily watering coco, I think anything over a pint per plant could cause a flood.
Let me know your average RH and info about ventilation. How much perlite is mixed and how frequently do you normally water. With that I can try to refine estimate. It is less than what you thinking

[GreenhouseEffect]

Definitely second keeping an eye on whatever you choose, for a few days, before you leave.
Sometimes I think watching it for a day will be enough, but I am always wrong when I do that, always takes me a few days to make sure I didn't overlook anything.

[roperman]

Had it going all day yesterday at the 2 quarts a day per plant rate. All good, no runoff. It's actually a lot easier than hand watering - no spilling or getting on leaves. I'll probably continue to use the pump when I get back.

Coco to perlite is at 2:1 ratio. My cloth pots are 5 gallons. If I let them dry out for a few days, each pot can easily take 5 quarts with 1 quart running off.

RH is pretty high, about 60%, temp is about 75 when the lights are on, 65 - 70 when lights are off. I know that RH is not so good for late flower, but I have a few weeks before I hit that.

My watering schedule has been an ongoing process. This is my first coco grow andI was using the knuckle test to determine when to water and was going 4 to 5 days before watering. I learned (from this forum) that coco can be watered daily, so I switched to between every day and every two days, alternating nutes and calmag water. Not sure why my pots can take nearly 4 quarts without runoff, but the plants are doing great now. Had a little nute burn which surprised me, using the half strength GH schedule. Using less Micro now than before. Also had some calcium deficiency (yellow spotting) and found that the pH needs to be above or around 6.2 so it can be taken up by the plant. I was feeding and watering at pH 5.7 - 6.1 which I guess was too low. I've decided to water at pH 6.3 and feed at pH 5.8. Sound ok, or should I mix up the pH even more?

Thanks for your input.

[Campesino]

If I let my pots dry out for a few days they could take that much water too. Be careful, because you are not going to let the coco dry.
I keep my pH range closer than that, but shouldn't be an issue. It is a good idea to let pH very somewhat. I haven't had pH issues with mature plants - just seedlings in Coco.
Hopefully you can monitor your set-up for a few days before leaving!