Yellowing, burnt tips (N+K?)

[totaln00b]

Bag seed. Day 6 of flower. Germinated seed to flower in ~28 days. Temps 79-89. Shultz Potting Soil (8-12-8) no nutes during veg. Started feeding PBP at 1/2 strength at onset of flower. Going to increase to full strength soon. Considering transplanting to more nute rich soil but not sure if it is too late. Under 150W CFL in a ~2 sq.ft. area. I think the def.'s are N and K... let me know. They also had some pests, I think thrips or springtails, but they seem to be gone now after Neem oil treatments (haven't done any since flower started) and I also did not water them for about a week to dry out the soil.

 

[Guest]

I'd up the PBP, add in some CalMag (as PBP is known to lack Calcium) and transplant into soil mixed with dolomite lime (to prevent pH issues).... that should fix it all!

 

[HeadyPete]

The yellowing is lack of N, due to the fact that there were no nutes during grow, and the leaf tip burn is normal for a good bloom nute strength. This is what tells you your nute strength is spot on. As they progress into flowering, they will take more bloom nutes, just watch that tip burn and keep it right as it is. The bottom leaves yellowing evenly is a normal result of reducing N during bloom. Lots of growers purposely reduce, then eliminate N during bloom, to give the plant better taste and burnability. Some pix show beautiful, full buds with yellowed or multicoloured leaves as the underlying colours come out as the green chlorophyll decreases from lack of N. The plants don't need N at this point.

No use transplanting now.

If you begin to see blotchy brown spots forming on the edges or inside the leaves, then you are into some magnesium or possibly calcium issues. The most important factor is PH. Make sure the water runoff from the bottom of the pot is reading neutral (6.8 - 7.0). All the nutes added in the world will not help if PH is out because the plants will not be able to use them. This is called nute lock.

 

[totaln00b]

Sounds like I need some CalMag and PH (litmus?) strips. I have seen some brown stuff, but those leaves were cut off so you can't see them now. About how much should CalMag and the PH testing cost? Can I get them at a normal store or do I have to go to a hydro store?

Thanks for the help guys.

 

[Guest]

Actually, skip the CalMag and just buy epsom salts... I think the dose is 2tblspn per gallon of water but you should verify that before dosing her.

 

[HeadyPete]

There is no calcium in epsom salts. If you have a calcium def then epsom will not help. Only magnesium in epsom. Dolomite lime added and cooked into your soil at least 2 weeks before use will provide cal and mag, and buffer the ph. Some strains are cal and/or mag hogs so the strain will tell you what it wants. CalMag is the best for that purpose of adding extra.

Do not add anything until you know your PH. Adding more could be disaster and I don't know where this school of though came from where if it's fucked, pile some more on. That is wrong. Nute lock from out of whack ph renders nutes in your soil unavailable for the plant to use, mimicking a lack of nutes. Adding more will make the problem worse.

You can get pool ph test strips from anywhere they sell pool products. You can get ph probes at any garden supply place. You can get electronic testers from better gardening and hydro shops. All work and you will probably pay more at the hydro shop.

Water you pots good with plain, neutral (ph7.0) water, collect the runoff at the bottom, and test ph.

Make sure any water or nute solution you add after that is ph 6.8 - 7.0 before adding. Soil naturally drifts toward acid ph and also fish and guano based nutes tend to be acidic.

That shultz soil is heavy in the phosphorus for bloom so that may be an issue and that is chemmy crap. Lookup moonshine mix and go organic with your soil and nutes and do yourself and your health a favour.

Good luck