PLEASE HELP! Your transition to LED & Watering

I am finishing veg with my first LED grow and having some challenges getting everything dialed in.

With my CFL grows, I always watered every 3-4 days. Nutes every other watering meant once a week with nutes, once a week without, all good.

With the lack of heat (I assume) plants now only need to be watered once a week.

I just want to make sure this is normal and I am not ignoring some other issue causing the plants to use less water.

Did you experience the same thing - watering cut in half?

How did you adapt - 1/2 strength nutes every watering, don't fully saturate, only give them then nutes evey other week, etc?

Your help is GREATLY appreciated.

Your grow should be kept at the same temp no matter what lights or season or whatever......

Yea they use a lot less water when cold...not good......slowed growth more likely to have lockout/deficiencies and root rot etc...

Transpiring slower means more nutes..when its hot outside is when you cut back, it just flows through em

qwizoking said:

Your grow should be kept at the same temp no matter what lights or season or whatever......

Yea they use a lot less water when cold...not good......slowed growth more likely to have lockout/deficiencies and root rot etc...

Transpiring slower means more nutes..when its hot outside is when you cut back, it just flows through em

Click to expand...

Ha, totally agreed, first thought that came into my head when I read the question.

Regardless of your technical setup, remember the basics. Water, air, temps, humidity should be in the range the plants are happiest in. Reducing water/feeding because your environment is wrong is like trying to fix a broken/leaky water pipe by putting duct tape on it…

Figure out what you need in your environment to get the temps/humidity right… the rest is easy…

Hey GrowinDad: All is good and that is normal with LED's. Like you I am vegging with a CFL and notice the plants drink more under it than the LED's. It is not uncommon for me to water once every 5,6 or even 7 days. I like for 2" of medium get pretty dry before I water.

My temps are in the colder range and that causes them to drink even less. My lights off temps average in the upper 50's to lower 60's depending on stage of flower. The later the stage the colder I get it. I kept The Doctor in 40's for about 3 weeks and she turned out to be something very special. Not saying anyone should try this. It just works for me. I just think my plants take on my personality and like colder weather.

As far as feeding goes. I sock it to them and give them full strength every watering. I also flush the last week. I might give them straight water once throughout the entire flowering cycle.

Just watch the leaves. They will tell you when they are in need.

Good luck.

Jeff over at Area51 recommended I cut some holes in my pots to increase evaporation. My pots have drain holes of course, he was talking about higher up on the sides to get more airflow in. He also recommended going with airpots or smartpots for soil grow in the future.

The leaves are telling me they are hungry but they are moist with full nutes. So I suspect they aren't absorbing well right now. My soil mix has lots of perlite so I am not worried about them drowning or anything.

Tent is at 74 degrees and 40 percent humidity right now. So it's not bad. But CFLs added a lot of heat so unless I want to keep my office, where the tent sits, at 80 degrees, moving to LED will cause less heat in the tent. I did just throw a 60W incandescent bulb in there to add some heat. But I think I may try drilling in some holes like Jeff suggested.

Im in the same boat here... don't quite have it figured out

During summer, the plants will wilt a little bit.. then I know to water.
Now with winter/fall.. the plants basically never wilt and always seem to have a level of moisture that can last well over a week. They are not quite perky.. and they just never fully dry out.. lol

So it's hard to tell the Best time to water.. but i just go by weight of the pot

fyi, temps are like 70-76 with 38%ish humid

im very noob, i roughly water once a week, i thought they r happy when they almost looked like a V looking into the light, once it wasnt that straigth V and more horizontl i watered them, is that wrong? I built a DIY salvagin old parts, so i covered with only like 35W...even after a week the soil was moist and they looked kinda sad. Now its again like 25°C before @ 19-20°C

Im fairly certain " praying" is a mag def

GrowinDad: Smart pots have worked out very well for me. I did a side by side of smart pots and air pots. I did not like the air pots and they did not produce the same results. They did dry out faster than the smart pots. That was one reason I did not like them.

How much do you water when you do? How much run off is there? If they are not absorbing then there will be more run off than normal. It sounds to me that everything is ok and that Jeff nailed it with the pot issue. If you think they are staying wet too long then use less water. Fans will help with evaporation too. I place a real small fan on the floor and let it blow right on the pots.

When I used HPS I would water every other day. I now water about once a week.

Multipass has the right idea about weight of the pot. That works too.

Airpot or smartpot have worked best for me, but you should be about 50% perlite and 50% soil. You can also add a little dolomite lime to help with the cals. and mag.

lol this made me just order some smartpots

Yes unfortunately there's a difference between soil drying faster from aerated pots and plant transpiring faster sucking moisture via roots because of elevated temps....one has nutes going into the plant? Isn't that what the thread was started for......sorry was put in a bad mood few threads over......if I take it out on anyone else I apologize....hopefully the entire forum reads this lone hidden post

You are fine quizoking. I would say it had evolved. yes, soil staying wet was making it gard for me to figure when to dose. Because If i water with just water, at this rate that would two weeks between nutes. So in theory anything that shortens the time between watering helps.

I water when the soil gets nice and dry.I water until I see a little runoff.

Will try air or smart pots next grow. Don't want to try to transplant these right now.

So here is the amazing thing... I put one 60w incandescent "grow"(bs!) bulb in the tent. Brought temp up to 78. I also drill some hole in the middle of the pots. No fucking joke after only about four hours I can already see a huge difference in the dryness at the top of the soil. I am hoping this gets me closer to my routine that has worked and now I can try to get them happier!

Thanks to all for the help!!

I used to think that over watering and root rot were something to fear....i no longer believe in any one of them....of course this is based on what i have experienced and is just one chumps version of events...

Reasons....oxygen to the root zone is key when working with LED's (probably any lighting actually) ...i can water as much as i like and keep the medium saturated

Solution...(was eluded too earlier) drill holes in your pots...more on the bottom and i also drill up the sides (about 4cm from the bottom) this keeps air moving through I can still have a run off (pot sitting in water/nute solution...although i still try and keep it minimal as fresh nutes/water is best)

It is also good for my micro herd if the medium remains damn....(only applicable to organix of course...)

So in my case....it is preferable that my soil never dries...and 'dormantices'...

How many holes did you drill in the sides of the pots? 2? 4? I am also having this problem growing in 1gallon pots.

These are only 2 litre pots....go for gold...

the solution to your problem is to add some HO T5 side lighting. T5s will add a little bit of heat, provide more light penetration into the canopy, and it will round out the spectrum for the LEDs. LEDs unless you have high end units like apaches, tend to be lacking. It will also even out light distribution since T5s spread across the whole length of the grow area. Think of getting an even tan in a tanning bed!

Less heat in the canopy results in less transpiration, but not necessarily less photosynthesis or growth. As chronikool pointed out if you are growing organically it is better never to get super dry and moist soil is your best bet.

These ladies are in 5 gallon buckets that have no drainage holes. They will blow up out of control under these conditions. Canopy temp is 70-75f because the heat from the flowering rooms is flowing through this veg room.


There are other factors, if you just recently potted up into moist soil it may be awhile before you should give a deep watering. On the other hand if the plant is in need of a pot up it will get thirsty every few days even under LED. The best way is to gauge whether to water is to hoist the plant a bit and judge based on the weight.

I drilled about four 1/4" holes in the middle of each pot.

I don't know Supra, I have had root rot and my girls seem to thrive when they dry out nice. But I am not using organics.

Mine have been growing fine I believe, first time with the strain. But they are showing signs of something wrong. This is my fourth grow. I have a comfort place where I feel in control of the grow and I am trying to get this grow into it.

When I get into my office this morning I will cut a couple leaves to get good pics of the issues. But again, my issue has been adapting my water/feed schedule to the new lighting and keeping the plants happy.

I did a 12-12 from clone test with the led to test it out when I first got it. They were in one gal pots and i didn't have any issues. My normal routine went fine. So i thought i was all set for this full out grow and got caught by surprise.

Pics of leaves...

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