Sick Seedlings

[P'appleChunk]

Seedlings are yellowing and leaves are necrotic or burned at the tips. Plants in solution 10 days and I think I over fertilized the first 3 - 4 days. They were under 300W LED's until just now, when I switched to 125W CFL for less color and more "sun" light, and, honestly, grasping. Nutrient bath is Fox Farms Big Bloom/Grow Big mix at 890 Ppm. Ph is okay, 6.7 and the room temp is always right at 75 fh.

First attempt at hydro, chose water culture for simplicity and small need. Probably 3 - 4 plants max in 3 X 3 grow room. First time on this , or any, growers' forum. I'd appreciate suggestions from more experienced growers in particular. And I'm relatively sure that's anyone reading! It appears I can add pix. If so there will be a few.


Thanks for your time

[Katzie_Wolf71]

Use straight water till they recover then use less nutrients after they recover is what i am thinking.

[P'appleChunk]

I'll give that a try and post results. Think I should use a flush, like Sledgehammer as well?

[Katzie_Wolf71]

I havent grown hydroponically but have read quite a bit on the subject and introducing that sledgehammer could give you more problems so i'd go on the safe side and just use ph'd water till it recovers. I dont use flushing agents at all and i grow in soil and my weed has always smoke smooth and clean.

[thegreengrower]

From what you say it sounds like you have over fed them. And again for hydro your PH is too high. Ideally you want to aim for a PH of 5:5-5:8, a little higher is OK but I'd say don't go any higher than say 6:2. So just give your babies water only at the right PHand they should pick up pretty soon. When you feed your plants the product will tell you to add say 2ml per litre. Always add 1/2 the recommended dose and slowly build up. You have to be extra vigilante growing hydro as you are in complete control and have no buffer to act as a safety net. For seedlings in hydro I always start off about EC 0:5-0:8 PH 5:7. Hope this helps.

[P'appleChunk]

Thx greengrower. I moved both to pure water and adjusted Ph to 5.6. Will monitor for 48-72 hours

Second question. In water culture system, does the bath have to be drained and replaced under normal circumstances? I assumed based, upon the feeding chart from Fox Farms, you utilized the same bath, augmenting nutrients thru the entire grow cycle.

[thegreengrower]

I think its always best to change your water/nutes after about 10-14 days. Like I said before, always use 1/2 recommended dose and you won't go wrong. Keep an eye on the pH as well. Don't worry though if it fluctuates a few points as this is normal and showing you that the plants are growing quite normally. If you keep adding pH down to keep it in the range of 5:5-5:8 then you'll be causing yourself unnecessary problems. Just let them do what they do. Growing hydro for a first grow is well, jumping in at the deep end, as you are in complete control. Its always best to start off in soil, learn about your plants and then move to hydro if that's what you want. That said, don't be put off coz its not that hard really. Just needs a lot of extra vigilance.

[P'appleChunk]

struggling with two surviving plants. questions for experienced hydro farmers...is it best to measure nutrient reservoir with Ppm meter or TDC?
Also, if using Ppm, do you add the reading of plain water to the nutrients? Ex: clear water measured at 204,w/o nutrients. If I want 400Ppm with nutrients, do I want a total reading of 604? Help!!!

[Joker1952]

It doesn't matter what kind of meter you use. Hopefully there will be a chart to check ppm to ec calibrations. I use even less nutes than greengrower- starting at 1/4 and increasing every week to 10 days when I change the res. I'm growing individual hydro set ups so each plant has it's own res. And yes, add the ppm of the water-if you want a ppm of 400, if the ppm of the water is 200 you want a ppm of 600-, just like your example. I top off with pH balanced water (5.8-6) between changing out the res- mine only hold 2 1/2 gallons. I like the tape that registers from pH 5.5 to 8.