Can anyone identify this symptom on the top leaves?
- Thread starter plan500
- Start date
Hey buddy hope your doing well.I have this issue coming up with every grow, usually in week 6 and it affects about 20% of all plants. This has been going on for 4-5 grows and I wonder what is it and should I do something about it. Rest of plants are ok.
Garden looks great.
Just a little deficiency.
Are you in soil?
How are what are you feeding?
Stay safe
Bill284
Looks like a typical case of not enough of one or more nutrients. Not all of the plants will react the same way so some of them will start to show the issue and some will not. This is why you notice that it affects about 20% of them and the rest can look OK.
Since it shows up in every grow and shows at week 6 it is saying that this is a repeating issue which will help narrow down what is causing it.
Several questions will help the group pinpoint things you can try. What are the plants being grown in? What line of fertilizer are you using? What is the fertilizing schedule you are using?
Are you using a pk boost?
Wastei
Well-Known Member
My bet it is on low pH if it's regular peat based potting mix? You need to add back buffers in peat or pH compensate in late flower to not let pH crash and being very low leaving minerals out of range. Ca is the first one to go followed by Mg and in severe cases molybdenum.
pH goes low in late flower since the plants releases acids in search of phosphorous that's normally low in native soils. Peat has a natural pH of 3.5-4.5.
We need to compensate for this with either adding back lime with Ca/Mg "Calmag" solution, silicates, potassium bicarbonate or gypsum in mid flower. They are the only real options to add back buffers in mid to late flower, the other option is to pH compensate by having higher pH on the input.
Hope that makes sense.!
Cheers!
pH goes low in late flower since the plants releases acids in search of phosphorous that's normally low in native soils. Peat has a natural pH of 3.5-4.5.
We need to compensate for this with either adding back lime with Ca/Mg "Calmag" solution, silicates, potassium bicarbonate or gypsum in mid flower. They are the only real options to add back buffers in mid to late flower, the other option is to pH compensate by having higher pH on the input.
Hope that makes sense.!
Cheers!
- Thread starter
- #6
Hi, thanks for the replay. I grow in Plagron light mix, which is a peat-based light soil with some perlite. I use the Plagron nutrient line, about 75% of recommended. More specifically the Alga line which is organic. I grow the plants 3 weeks in 2 gallon pots and flip them for another 8 weeks of flower under Led 300-700 PPFD start to finish. These are my total PPMs starting from week 1 flower till the end. What do you think, is this on the lower end considering the plants size (short veg)?
| 313 | 411 | 570 | 875 | 1032 | 1189 | 1250 | 750 |
And this is my cal/mag for the same period. Manufacturer recommends a max of 1 ml/L.
| 0.1 ml/L | 0.3 ml/L | 0.5 ml/L | 1.0 ml/L | 1.0 ml/L | 1.0 ml/L | 1.0 ml/L | 0.5 ml/L |
So I am either underfeeding, or they need more cal/mag in weeks 2 and 3 as well.
- Thread starter
- #7
I do, Green Sensation, its from the same nutrient company.
- Thread starter
- #8
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Honestly I have lost years in chasing pH in soil, tested hundreds of theories, mixing different additives ect, so eventually I chose organic soil growing (Alga) so that it is all taken care by the organisms. It self regulates and that's all i want. I even add wormcasting teas with almost every watering to support the micro organisms and not having to deal with pH. So respefully I refuse to go that path ever again.
A very popular statement here over the past several years. A dog with a cropped tail has a better chance of catching the stub than most gardeners do in figuring out the pH in their soil, especially the water than ran though and is in the saucer.
Though Wastei did mention a peat based potting mix which brings up the question of just how much peat makes it 'peat based'. Is it 33% or is it a larger percentage? I just mention the 33% for starters since that has been the standard for decades when it comes to mixing up potting soils....1/3 of peat moss, 1/3 compost or quality 'dirt', and 1/3 Perlite.
- Thread starter
- #10
Lightmix is for growing profitably and fertilizing your plants at your own insight.
Lightmix is priced economally and minimally fertilized. It's an airy substrate because of peat and worm castings and it has good drainage because of the added perlite.
plagron.com
It is mostly peat and some perlite. I have consulted with the company in the past and they claim the soil works good with their Alga - organic series. That's algae based btw.
I was wondering what percentage of peat made a "peat based potting mix" as Wastei brings up. Some of the mixes I have noticed being mentioned over the years are 33%, some 50% and a few that seem to go as much 66 or 75%.
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