Hey all, I'm doing a grow of some bagseed right now and it's going great except for one problem - the plants are barely growing. It's been almost 4 weeks and they're between 3.5 inches to 7 inches in height, most around 4-5 inches tall. A few details: -Medium: Soil (using store-bought organic potting soil mixed w/ perlite), using 3:1 soil/perlite ratio by volume. -Lighting: I've got a couple going in a grow box with 200W+ of CFLs, and 4 going under a 250W HPS in a closet. -Temps: In the grow box it's a pretty steady 75-80 degrees. The HPS closet varies from mid 70s to low 80s, never above 85 F. Humidity: 30%-50% -Air circulation: Grow box has a 60 CFM fan (worked fine for the last grow in it), closet has a desk fan blowing on the plants, door is kept open. -Watering: I've tried adding ferts and not adding ferts (to correct the problem). A few of the plants got very slightly burned a couple weeks back but they look healthy and green now that I'm using plain water. -pH range: My tap water and runoff water are both in the 6-7 range. I didn't pH during my last grow and it turned out fine. I've used the grow box before for an earlier grow and the plants in it grew way faster. I used the same soil, same perlite, same nutrient feeding schedule (except when I fiddled with it a little to try to fix the problem... adding more/fewer nutes seems to have done nothing). The only problem I can think of is the soil - it seems to be packing down a little bit and it takes forever to dry out between waterings. When it dries out completely a couple inches down I'll water and the plants will grow 2-3 inches and stop growing until I can water again. I'm guessing I need to break up the soil a little and be careful not to compact it by watering too quickly. Does anyone have a good way to do this for plants that are already potted (without damaging them)? I have all the plants in 2-gallon trash cans (w/ holes drilled in the bottom for drainage) and I don't intend to re-pot them. I can post pictures or more information if you guys want. There wouldn't be much to see from pictures...they all just look a few weeks younger than they are. The leaves are "folding" along the central vein a little bit (symptom of over-watering?), but it's barely noticeable.
I had the same problem recently. See pics, same plant 16 days apart. I am sure it was the SOIL - Miracle Grow which has slo release ferts, and unstable pH of my water. I took them out of their pots by overturning the pot while supporting the seedling between 2 fingers. Broke away as much soil as I could. Put the roots into water that was pH 6.5 and a drop of Superthrive. Refilled the pot with Fox Farm Ocean Forest soil - mainly worm castings. I saw almost immediate improvement. and you can see the difference between then and 16 days later.
Yeah I hear MG soil sucks. I just use a potting mix my local garden center sells (it's the store brand). It says it's got compost, humus, and peat moss in it. Either way, it worked fine on my last grow (I used the same brand of soil that time as this time). I suppose it's possible that the bag of soil I used this time around had more clay in it or was somehow different from the bag I used on my first grow. I've never seen FF Ocean Forest for sale in my area, though I hear it's pretty much the best soil to use. If you don't mind my asking, what store did you get yours from? Oh and good to see your plant is doing well!
Try a local hydroponics store. google search for one new you. they usually carry all the Fox Farms stuff. with the MG, my soil seemed packed too, would never dry and i wasnt over watering. The stunted grwoth was also from lack of trace nutrient uptake. soil will get acidic withh too many nutes and then the plants metabolize. I was surprised to buy one gallon of distilled water and found the pH to be 8.5. And my tap water fluctuates. now i NEVER feed or water with testing. good luck!
It may not hurt to loosen up the soil a little and add some more perlite. Compacted soil is definately not what you want, but shouldn't cause big plant problems. Your biggest enemies are gonna be overwatering and nute overload. Keep both balanced and your plants will let you know it!