When to water if soil is not drying?

[greenops]

I got a 2 plants ScrOG going at the moment. They've been flowering for a week now in 3 gallon pots.

I noticed that even 7 days after watering, the soil isnt drying out as it should.
Normally I would wait til 2 inches of the top soil gets dry, but the growth rate drops significantly after 5 days of watering and the leaves start to droop!
The growth visually stops after 6 days.
Thats why I water them again after 6 days although only an inch of the top soil gets dry, and the pot still feels a lil on the heavy side.
After each watering the growth picks up again.

I'm using Plagron Grow Mix (with perlite).
Last time I watered with 6.4 pH, run off was 6.8 pH.

Question:

When should I water?

It will put me weeks behind of schedule if I wait til the soil is dry enough...

Will I be over-watering my plants if I keep on watering them while the soil is still moist?

Thanks!

 

[Green Supreme]

Perhaps your root zone temps are too low. Many plants have difficulty processing food and water while their roots are cold. Good luck. Peace GS

 

[greenops]

I dont think so, cuz my temps are 70 - 85F.

 

[Green Supreme]

At root level? Peace GS

 

[greenops]

ummm nope! I dont have a way to measure the temps down there...

 

[Mrpiston38]

what are ur temps after lights are out durring hrs 4-5 of the cycle? this is the temp he is asking for. just my 2 cents and if it does get chilly u can get a space heater on a timer to only kick on dyrring the coldest part of ur night, if that could be ur issue pics would help too. what kind of lights, extraction, how old are they plants. it also my be that they "could" be rootbound? how long have they been in the 3gal's? sry to ramble but more info will help.

Mr.P

 

[Mrpiston38]

u can take a thermomiter u put in ur mouth to take ur temp when ur sick? lol
hey it might work

 

[greenops]

what are ur temps after lights are out durring hrs 4-5 of the cycle? this is the temp he is asking for. just my 2 cents and if it does get chilly u can get a space heater on a timer to only kick on dyrring the coldest part of ur night, if that could be ur issue pics would help too. what kind of lights, extraction, how old are they plants. it also my be that they "could" be rootbound? how long have they been in the 3gal's? sry to ramble but more info will help.

Mr.P

lights out the temps are 21C/70F.

I'm using 250w HPS, and theyre prolly about 50-60 days old in total. All I know its their 8th day flowering.

I think i can rule out that they are root bound.

The thing is, i can feel the bottom soil thru the drainage holes, and they do feel dry after 3 days of watering. Its the top soil that remains moist.

 

[Mrpiston38]

u might want to trip up the underbrush or maybe get a small fan to blow under it to help? i think those 2 things would help ya. gl

 

[greenops]

Ok, i'm using my 2nd fan now... thx for the tip...

 

[señorsloth]

ya the fan is a good idea, if your pots are drying from the bottom up, then that would indicate to me that you have no roots near the surface level...did you transplant at all? i have found that if you bury a small rootball at the very bottom of a much taller pot, the roots can have trouble growing upwards, they mostly only want to go horizontally, and down, but never up, so that top 2/3 of the pot remains unrooted throughout the grow(though only if you flower soon after). i suppose this could cause the soil to dry from the bottom up.

in the end, if there were roots in that soil then it would dry just like the soil on top. the fact that it stays wet, makes me assume that there aren't any roots in there. that being the case, root rot(the reason we don't let the soil stay wet all the time)can't happen, so you should be able to ignore the top layer, and water when your plant needs it, not the pot. maybe even try getting some of the excess, always wet soil, out of the pots, and then adding it back later if needed so that the soil dries normally

 

[sso]

well, they look fine apart from some waterstress.

lack of watering looks like.

soo..

if everything is fine (nice leaves btw) and no probs, why not simply water each 5th day when they need it? regardless of whether the top soil is moist? (fine anyway)

 

[White-rhino]

I usually lift pots, and when they start feeling light, give a dose of water.

 

[lowdesertsun]

ya the fan is a good idea, if your pots are drying from the bottom up, then that would indicate to me that you have no roots near the surface level...did you transplant at all? i have found that if you bury a small rootball at the very bottom of a much taller pot, the roots can have trouble growing upwards, they mostly only want to go horizontally, and down, but never up, so that top 2/3 of the pot remains unrooted throughout the grow(though only if you flower soon after). i suppose this could cause the soil to dry from the bottom up.

in the end, if there were roots in that soil then it would dry just like the soil on top. the fact that it stays wet, makes me assume that there aren't any roots in there. that being the case, root rot(the reason we don't let the soil stay wet all the time)can't happen, so you should be able to ignore the top layer, and water when your plant needs it, not the pot. maybe even try getting some of the excess, always wet soil, out of the pots, and then adding it back later if needed so that the soil dries normally

Hi guys, I think seniorslot is right, dont water them from above anymore, just put your pot in a bigger pot for 15 min, so the lower roots can suck it up, a couple days the soil on top should dry out...
peace

 

[señorsloth]

lol well i didn't say to do that...i'm not sure if i'm right but ive always been afraid to water from the bottom up, because it has a tenancy to over saturate the soil, pushing all the oxygen out, makes damping off even easier to get...

 

[greenops]

I cant water the pots from the bottom cuz its a SCROG... so the pots cant be moved anymore

 

[dubwise]

I'm not a soil guy, but perhaps you could insert a probe a little ways down and water through the probe...bypassing the top portion of the soil directly. We use this method outdoors in some raised beds (veggies) and it works pretty well. We do this with tomato plants and they love it.

 

[moonymonkey]

maybe tryi leting soil dry out until plant drops...do you water until water comes out bottom of pot?if so i wud measure the amount of water it takes to water wen it drops for it to drain out bottom versuses the amount you were using before,...trying to use the least amount to drain out bottom...checking to see if growth improves...and starts taking up water faster or like it should acording to growth shown not sure if this helps,but done that in past...peace moon/

 

[LifeLess]

People who said a fan under the canopy were right. I have a 4 plant scrog going right now. Before i put the fan in i was watering every 5 days. Now its seems im watering every 2 days. A comp fan might not move enough air so you might need to get something bigger. GL LL