Plant is unhappy, can't figure out what it is

[DonnyDee]

Hi folks

My seedlings are just around 2 weeks old, I've been watering them with PH-ed water, after 10 days I fed with 200ppm worth nutrients, specifically, I gave the bottoms a quick dunk on the nutrient solution. The roots are exploding out the bottom, which is great, but the leaves aren't looking too happy in general. One plant specifically is showing purple under the leaves.





I thought it was overwatering at first, but they've pretty much dried up and are still not looking happy. Could I have introduced nutrients too early?

Temperatures are around 20c (68F) with RH around 35%. I give them a boost to 25c (77F) and 70% RH around 3 times a day. I moved them from 30W led to a more serious cob fixture putting out around 100W over the weekend, could this be light's doing - they're around 15" away?

They just don't seem to be happy. I'm currently planning on watering them again, with just PH-ed RO water, but I want them to dry out nicely before I do so, so will keep an eye out for signs of underwatering before I do that.

[Bulls]

Increase the distance between the COB and the Plant. 30 Inches to start with and go from there. Also your RH is low. Bring it up to over 55% and increase the temp to about 24-28.

p.s make sure your PH pen is daily calibrated and you keep your ph at 5.8.

[TomKing]

Have you been using RO water since the start? And Do you use calmag?

[DonnyDee]

Have you been using RO water since the start? And Do you use calmag?

I initially soaked the rockwool cubes in PHd RO water with 200ppm calmag. I'm currently using a 3-1-2 with 3.6 Calcium and 0.5 magnesium, at 200 ppm.

[M_C]

What PH is your water?

[DonnyDee]

What PH is your water?

I try to aim for 5.8 using an indicator. Ph pen arriving today, so will have it more accurate in the future

[Bulls]

I try to aim for 5.8 using an indicator. Ph pen arriving today, so will have it more accurate in the future

Problem solved.

[DonnyDee]

Problem solved.

After getting all temperatures etc correct, I see I was hitting them with 5.5! Hopefully that's the issue. I'll be giving the rockwool a couple of gentle sprays with some 300ppm nutes PH-ed to 5.9 over the course of the next few days, keeping it as dry as reasonable, as it seems the wrinkling/swelling in the leaves may also be overwatering. Have also upped my thermostat to 25c.

Thanks very much for the advice, hopefully they'll get back to being happy little (please be) ladies soon!

[ReeferDankness]

Don't worry about over watering. Rockwool drains fairly quick and the roots can get plenty of oxygen if they are bursting out... I did a grow with rockwool where I had the feed on 20/7 and never had over watering issues.

I normally only give my seedlings water until they are about the size of yours then I start feeding... initially I don't even PH the water and they seem to do fine like that for 2 weeks then require feed.

I'd say that you've possibly added to much nutrients or PH +/- to balance the PH... How do you add the PH+/-?

[DonnyDee]

Hey again folks

Plants are looking far happier, but I'm worried I may have some mildew and some small brown spots are appearing on my leaves. Can anyone help identify what may be causing the spots and whether this is mildew - or dried silica from my neem/silica foliar spray?







Thanks all!