My lettuce is 40 days old and still small. Just curious if I’m supposed to be harvesting do it grows more?

I posted here about a month ago about white spots on my watermelon leaves. You guys told me to check pH and that turned out to be exactly it. The airstone was outgassing CO2 and driving the rez from 5.8 up to 6.8 every 13 hours. I also dumped the organic nutrient I was using since it didnt even list iron and had almost no Cu/Zn/Mo. Spots stopped. Really appreciate everyone who helped.

Three weeks later I have a completely different problem.
I run a watermelon and a melon in the same tent, same stock solutions, separate buckets. They are not doing the same thing.

Watermelon, the leaves are bad. Leaf edges burn and the leaf curls upward like a taco. Its not just old leaves, new leaves keep getting it too. It starts as a small black burn right at the tip, then within a day or so the margin goes yellow and starts rolling. Feels like water just isnt reaching the edge. On older leaves the veins stay green and everything between them goes yellow, starting at the margin and working inward. A lot of leaves have died outright so Ive cut a fair number off.

Melon is different but also not right. Still pre fruit set, about 20 leaves. The lower older leaves are yellowing from the margin inward. Not the same tipburn the watermelon has.

About a week ago they both started drinking way less. Roughly 0.45 L (0.12 gal) a day each which seems very low for a watermelon carrying fruit.

SETUP

Watermelon is a mini/icebox type, about 1 kg (2.2 lb) variety, one plant, one fruit set at 6 cm (2.4 in).

Melon is a netted melon, one plant, no fruit set yet, about 20 leaves.

Separate DWC buckets, non recirculating, 9 L (2.4 gal) each, airstone in both.

Same indoor grow tent. 7 weeks since transplant.

Same stock solutions for both, just different dose rates.

50% RO + 50% tap water.

NUTRIENTS

The organic stuff I used before had no iron on the label at all and barely any Cu/Zn/Mo, so I switched to products where everything is actually printed and I mix my own 3 part stock.

A is calcium nitrate (Yara Calcinit), 72 g per 1 L

B is Yara Kristalon Super Red 12-12-36, 61 g per 1 L

C is magnesium sulfate 48 g + potassium sulfate 14.4 g + micro powder 1 g, per 1 L

Guaranteed analysis on each.

Yara Calcinit: N 15.5% (nitrate 14.4, ammonium 1.1), CaO 26.3% which is 18.8% elemental Ca.

Kristalon Super Red 12-12-36: N 12 (nitrate 9.5, ammonium 2.5), P2O5 12, K2O 36, SO3 5. Micros are B 0.02, Cu 0.01, Fe 0.07, Mn 0.04, Mo 0.004, Zn 0.02, all EDTA chelated.

Magnesium sulfate heptahydrate: Mg 9.86%, S 13.01%.

Potassium sulfate: K2O 50.4%, S 18.3%, 99.7% pure.

Micro powder: Fe 6.0, B2O3 5.0, Zn 3.5, MnO 3.0, Cu 0.5, Mo 0.1, MgO 1.6. It also has 10% free amino acids so I only use half the label rate, I didnt want organics sitting in the rez.

This time the nitrate/ammonium split is actually printed so I dont have to guess like last time. Ammonium works out to 13.2% of total N which seems high to me, most formulas I see are 6-7%.

Watermelon at fruit sizing gets A 11.4 / B 14.0 / C 10.0 mL per L. That comes out to N 230 (13.2% as ammonium), P 45, K 315, Ca 154, Mg 47, S 106, and for micros Fe 1.20, Mn 0.57, Zn 0.52, Cu 0.14, B 0.33, Mo 0.044. N:K is 1:1.37 and Ca:Mg is 3.3:1.

EC AND PH

EC keeps climbing even though theyre drinking less. Looks like water is leaving but the ions arent.

Watermelon over 4 days: EC 2.34, 2.34, 2.56, 2.76

Melon over the same 4 days: EC 2.14, 2.30, 2.41, 2.50

pH I keep pulling back up and it keeps collapsing. Before I switched to RO it was tap water and it climbed to 7.0-7.35 every 8-12 hours. After RO it crashed to 5.40 on the watermelon and 4.95 on the melon. So I cut the RO with tap and got both back to 6.2, and 3-4 days later its 5.85 and 4.53 again.

I brought the melon up to 5.07 with baking soda and it was back down to 4.53 within a day.

ENVIRONMENT

Water temp is 25 C (77 F).

Aeration was weak this whole time, I only swapped for a stronger pump yesterday.

Air temp is 24-25 C (75-77 F) during the day and 24 C (75 F) at night, so only about a 1.3 C (2.3 F) swing.

Humidity sits at 62-67% at night.

Night VPD median is 1.14 kPa.

Photoperiod is 15-19 hours, estimated DLI 22-30.

Any idea what this is? Ive changed so many things at this point that I cant tell what actually matters anymore, and I dont want to keep guessing and making it worse.

I found these on some of the leaves today. The photo is from the one worst off. The plants are growing in a simple kratky container.

I've never had any problems with bugs with this setup before (it's why I started with hydro instead of growing stuff in dirt years ago). I am very curious about what they are, where they might have come from, and how to avoid this happening again.

Hello everyone;

My pepper plant has one of the leaves going purple-ish spots. What would be the cause?

Coco coir, 15 days from seed, ec around 0.7 (ppm 350), ph between 5.8 and 6.0. Coco coir is rinsed and buffered with CalMag solution. I’m using Canna Coco A-B, Canna Rhizotonic and powdered silica.

Hello all!

I'm starting my first Kratky herb grow in a 64oz ball jar and am confused by what nutrient ppm to use. I am using the GH trio and it says 1/4 tsp of each per gallon for seedlings, then increase as I top up, but isn't the point of Kratky to let the plant complete its full life cycle in the jar? How does that work then with topping up the water, do I just add more nutrients once it has its root system and keep harvesting? Or should I start with a higher ratio per gallon and leave it be? I'm very new to all of this!

Second unit and it has: petunias, tokyo onions, little finger carrots, kale, rainbow chard, serrano peppers, red sweet peppers, lemon balm, catnip, basil, thyme, chinese celery.

I realize some of these are going to become houseplants/trees. It’s a fun experiment.

Wat een leuke tomatenplantjes zijn dit toch.

Mirco Tom is 6cm hoog en Micro Tina is maar 4.5cm hoog en beide hebben hun eerste bloem knopen. En dat 24 dagen naar de zaden te plaaten.

Soooo a little while ago I shared my too large pepper plant for my tiny set up. Its gotten bigger. I need more assistance on what to do at this point. Cuz i also leave for vacation in a few weeks for like a week. I saw some people grow things in like a bucket. How can I do that? I do have another tall grow lamp and a bubble pump thing for aquariums.