I've been wanting to respond to your post for a bit but I haven't had the time to sit down and give you the attention you deserve!
I'd be super interested to hear about your microbial observations! I've got some books about soil bacteria on my amazon list, I'm hoping to start actually being able to identify the different bacteria. I have access to microscopes and I feel like I haven't really taken advantage of that resource as much as I can.
I haven't had my soil tested for microbiology yet, unfortunately! I am going to take a sample and hopefully get it sent in this week or next week, then I want to do another sample right when I cut down, and again a couple weeks after I've replanted.
I have also come to the conclusion that cover crops are a waste indoors (although I don't want to say waste cause that's not quite true). It's just the way that cover crops are supposed to work doesn't really fit with the way that indoor growing works (at least in an efficient manner). When growing outdoors, organic farmers will til their fields/plots/beds either in the fall with lots of organic matter that will break down over the winter, or will heavily apply manure and compost in the early spring a couple months before they actually plant their crops. They will grow the cover crop to start the nutrient cycling process, then they chop the crop and til into the soil before planting, the cover crop becomes what the professionals call green manure, supplying the plants with readily available nutrients and releasing fulvic and humic acids that help breakout down the minerals locked in the soil. Now, we can recreate this process inside for sure! However, growing inside uses up a lot of energy, and can be quite expensive. But the bonus is, you are not at the whim of the weather. So you can grow back to back crops, fitting more harvests in a year. So taking time out from those back to back harvests to grow a cover crop isn't really the best idea. (this is not in anyway discussing the three sisters cover crop method which is a whole different thing) That's why compost and castings that add readily available nutrients but not in an overabundance or precomposted soils are best for indoor organic grows. Fish fertilizers and fermented extracts as well but my focus is definitely on doing what I can to avoid liquid fertilizers and keep the plants healthy by fertilizing the soil in low amounts in a way that hopefully improves the quality of the soil tilth, encourages healthy microbial development, and maintains fertile soil.
My soil was definitely overfertilized my first round! Ph was too high because of it, and the first few weeks of plant growth were rough. After I added some sulfur to the soil and the plants got a little bigger the situation improved dramatically. I didn't fertilize for the rest of the round, my second round I didn't fertilized at all. Vegged for a little over a month before switching into flower. About five weeks or so into flower I had some yellowing in the beds that had my heavy eaters (skunk 47 mostly) so i top dressed in a pound and a half of all purpose bat guano into each bed. Didn't fertilize them after that. When I planted this current round I just added compost and castings and some rice hulls. As mentioned I've been mulching with worm castings every few weeks. Three weeks into flower I top dressed kelp meal into all the plants and tubs and pots.
Ah thank you for taking your time, what wonderful food for thought came of it!
I love your reasoning regarding the cover crops in indoor gardening!
Indeed, in their function as
intercropped fertilizer they just don't make sense in an artificial environment.
This also applies to having permanent ground cover growing to assure the
stability of the microbial herd!
The idea in this case is to have a mixed vegetation covering the soil always, with the main focus on having plants in that mix who have similar microbial needs as our desired crop. So when we go to sow, say corn (no-till! just poking holes in the ground and inserting seed, or worst case opening planting furrows), the microbial community corn needs is already fully active in the soil and the seedling can just click itself in (and into a mycorrhizal network that works for it too).
When we grow our cannabis back to back in our no-tills, we are getting the same effect automatically. Our time horizon is different than in the outdoors, and if we plant that next plant as soon as the old one is harvested, the microbial herd that fed the previous plant will still be there.
Cover crops, or maybe more correctly, ground cover, of course are also good for just
covering the soil, giving it
protection from sudden changes in temps, humidity, and the impact of the elements. But we can give our pot soils that with simple mulches, which add organic material back in too. Given our accelerated time cycle, that is probably the more effective way to go anyway.
That leaves possible allelopathic effects, but we can have those plants on the side, sitting in soil that is more suited to them. Plus our environments are generally less inhabited, even if we do tend to them in a nature-friendly way.
So yeah, so much for cover cropping/ground covering indoors!
I do admit, I am finding a chance companionship that established itself in one of my pots quite convenient though:
A borage sprouted itself when the previous plant, a Pineapple Express, was sprouting too, and its leaves would get mulched in every time they'd start overshadowing her. When she overtook it, it stopped growing, and remained a midget for the rest of the grow.
Towards the end, it then started blooming and another borage sprouted, which is now babysitting my seedling in the same manner as its brethren before.
It has something hand-and-glove to it, and the current Berry Bomb seems to approve
As for the microbial herd, I have a first story for you!
Today, I was able to confirm that when we see deficiencies in our plants, indeed, there is trouble with the life in the soil.
I had mixed up a nice compost-heavy potting mix for a NorthernLights#5xHaze seed, and microbially it was an active soil, if more on the bacterial side. I sprouted the seed directly in there (did you know that seeds put out exudates even
before sprouting, prepping up the microbial life outside for when it does!!), and she was quite happy for the first 8 days.
I still don't know exactly how I did it, but I managed to cause a microbe armageddon and on day 9, my baby girl greeted me with a bright yellow - everything! Like from one moment to another, she sucked all the nitrogen out of herself. So 3 days later and the comfrey I had watered & mulchged not helping, I looked at the soil life. And yeah, there were diverse bacteria and even some fungi, but
nooo cyclers. Not a flagellate, amoeba, or nematode in sight, not even anaerobic cyclers, like ciliates or rotifers.
So I did a number of things. Topdressed with older VC (that was kind of dormant though), fed them sprouts juice and comfrey, and went on to uppot her as soon as her roots started poking out the bottom holes. I had just harvested some VC, also very bacterial but with a heckload of flagellates, amoebae and nematodes doing their thing, so I used it to help repopulate those, which had been so strikingly missing from the soil before.
A few days later, the NLH is starting to green up, if still lightly.
When I went to check the soil today, I found a completely different picture:
A very diverse bacterial herd, beginnings of fungal growth, lots of amoebae and flagellates, and a nice nematode presence. Far from ideal, but clearly shifted, to something that is visibly becoming functional. Giving us a first glimpse of how indeed the health of the plant corellates to the state of the soil
ecosystem.
If this were an experiment, my proceeding would have to be deemed sloppy - bringing in so many variables with the changes I made without checking in between! But since we're just
observing, I'm allowed to do that
So I will continue to check the soil and the VC I add, while supplementing a bit with fresh plant juices and topdressings because I still think my soil mixes are a bit weak on the long-term nutes, no matter how much I say to myself,
it's the microbes babe, it's juust the microbes haha
See how the plant is doing, and how that reflects in the soil populations. Fun times!
Cheers!