Things are generally going well for my windowfarm. The herbs are starting to look like real plants, and the dwarf sugar peas are going nuts taking over the window. Unfortuantely, one plant isn’t doing so well and I haven’t yet figured out why.
The lower leaves have turned yellow and withered. At first I thought it was simply because they were stuck under the felt and not getting enough light, but now the outer edges of some of the other leaves are joining them.
Cursory research suggests that the plant may not be getting enough water, but if that were the case I would expect other plants in the system to have problems too since they’re all on the same watering schedule. The roots of the sick plant look healthy and have access to plenty of oxygen.
I did notice some suspicious build-up on the clay pellets near the sick plant. It’s possible that some sort of bacterial or fungal infection has managed to get a hold of the plant. If I can find a local source for food-grade hydrogen peroxide I may try flushing the system with a dilute solution of it. In retrospect, I should have sterilized my seeds before placing them in the root plugs for germination. Sterilizing the root plugs in the pressure cooker would have been smart as well.
I’m also trying to decide if it makes more sense to simply remove the troubled pot from the system to prevent the others from becoming contaminated. To do so would mean losing those two plants but I’d rather lose two than the whole column.
Some questions:
Where in the stack is the wilting pot? top? bottom?
Do you have others of the same variety in different pots?
That leaf damage looks like a systemic issue- I would guess too damp as more likely than too dry, but it could also be salt/mineral build-up. The white stuff on the pellets also looks like mineral build-up, so that would be my first guess.
From the little shot you showed of the sick plant, I don’t see any sign of a disease agent. That said, weakened plants are prone to secondary infections, so removing it might be beneficial in the long run.
My guess is there’s something you need to tweak in the setup to get the water and nutrient flow right. It would be the conservative thing to ditch the weak plant, but myself I would start tweaking and use the plant as a barometer to see if I was improving things. You may not get much food out of the stressed plant, but if you can turn it around so it starts looking healthier, that would be a good sign.
One note- It never hurts to prune. A systemic issue is almost always starting in the roots of the plant, and giving the roots less “canopy” to support reduces the stress on the system. I’d remove the damaged leaves and 30 – 50% of the leafy top, and go from there.
oh, another thing, sterile is probably not what you want. Most plants have beneficial bacteria that ride along on the seeds; this is certainly true of beans, which are legumes and grow special root structures to house bacteria that fix nitrogen. You would do better working to support a healthy culture.
*Something* is going to grow in that media; it’s exposed to the air. Establishing a healthy culture will stave off destructive strains of bacteria and fungi.
I had the same problem with the whilting leaves in one of my pots. I had located the pot above a heater. The problem went away when i put the plant in a cooler and more shaded area. You might want to try and see if there is a heater in the near proximity