That's where I ended up. I started with soilless (and GH Flora 3-part,
"Useless" schedule <<link). I think that's a
great way for new growers to start (with Pro-Mix HP & 25% more perlite. But, under HID I might not add the perlite, it could dry too fast. Especially HPS lights.
Promix HP has 35% perlite itself). It's hard to mess up. It's simple in the sense that it doesn't depend upon soil health, conflict with nutrients in the soil, etc.
It's basically hydro, with ease of growing one plant in soil (no hydro setup). The only downside is you have to pH the nutrient solution. In soil, you don't have to (if it's not overfed). Growing soilless can get a person started with practices that are bad for soil. I went through a period of overfeeding in soil because I was used to force-feeding in soilless. And the whole microbe health thing is important in soil, but not soilless. Switching to soil from soilless requires some different views. You suffered the opposite going from soil to soilless. You're feeding bennies to an organically inactive medium, feeding the lower soil-like strength.).
I got tired of the soilless/hydro bottles. I wanted to grow in soil with a simple soil fertilizer. I wanted more of a houseplant than a *project*.
For my soil: I mix 50-60% Pro-Mix HP[1] with 20-25% Kellogg's Patio Plus (potting mix) and 20-25% perlite. I add dolomite lime (Fertilome Hi-Yield Agricultural Lime) 1.5 Tbsp per gallon of mixed soil.[2] I fill the containers and soak them (and let dry) once or twice before growing to let the dolomite activate a little into the medium.[3]
The Patio Plus adds some organically-active material. But, the available nutrients are low enough (as part of the whole mix) that it only feeds a seedling for a week or two. (I start feeding 1/8-strength nutrients after a week, and move up to full strenght during the 2nd week.). The Patio Plus just makes the soilless materials "dirty" ("soiled") enough to promote organic activity. Compost might be better.
This is a photo of Patio Plus by itself:
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Patio Plus is 0.30-0.10-0.10 (which would be too hot by itself, and I don't think it's a good consistency by itself. It's a little woody which makes the soil consistency chunkier than I'd like. (But, it works well the way it's mixed.)
This next photo shows the final mix. The NPK should be about 0.7-0.02-0.02. (But, I'm extrapolating that based upon how I "dilute" it by volume with peat and perlite. NPK labels are based upon weight.).
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I like this consistency because it dries in 2-3 days (after a plant has grown into the container). I think cannabis likes those fast drench/dry cycles.
If I mix it more toward 60%-20%-20%, it dries faster. 50%-25%-25%, slower. I'm not precise about it. I use level scoops of Pro-Mix with heaping scoops of Kellogg's and perlite to get something in between.
Kellogg's isn't sexy. It's just Home Depot stuff. But, I have great results with it. (That's one reason I never have enough motivation to experiment with making my own Pro-Mix HP, or using compost or the Kellogg Palm & Cactus potting mix -- which looks like a very nice consistency of sand and other things. Not woody. I feel like using that would improve it. But.. this works very well for me.).
I feed Grow More - Sea Grow All Purpose (16-16-16) as my base. For all my dislike of multi-bottle "lineups," I ended up creating my own "schedule" using various generic fertilizer products. I mix various generic products to get my own NPK ratios. Like you said, I "read the plant" and have a few "blends" I can throw together.
I've attached a PDF showing how I feed in this soil. (The strengths are worked out to avoid salt buildup. But, I tend to mix enough volume for higher runoff than most soil growers would do. The runoff helps avoid salt buildup, letting me feed stronger. Coming from soilless (the way I did), I had that force-feeding mentality. Soil growers tend to think of keeping everything in the soil, not washing away microbes and things. I think (at least with this light soil), cannabis likes the plate cleaned between feedings. I think of it as giving the plant a fresher plate of food each feeding. Not trying to maintain unused nutrients in the soil in case the plant needs them (the typical "complete soil" approach).
So, it's a hybrid between soilless/synthetic (medium/nutrients) and soil/organic. I'm not fastidious about avoiding synthetic nutrients. But, I try to use organic sources of food if something's available. (E.g., I use inorganic potassium sulfate to raise K because I can't find anything organic to raise K. Ashes would wok. But, I want to be more in tune with the NPK ratio. I don't think I can do that with ashes. If I were creating a more complete/living/composted soil, where everything's available to the plant when it needs it, I'd use ashes. I want the benefits of both worlds. Some organic activity in the soil. But, more immediate delivery/control of nutrients. I reach for organic sources of nutrients when it fits my goal. Gypsum for Ca def instead of "
calmag" containing inorganic calcium nitrate, etc. But, I'm not religiously against inorganic sources. I just try to default to organic sources if they're relatively fast acting. It's a balancing act. I'll use epsom salt for Mg def. That's inorganic. But, I might use Langeinite if I want to adjust both K & Mg. It's organic, I think. Comes from mined material.).
If you do it the way you described, I would be careful to err on the light side. With all those amendments, you could end up like Fox Farms Ocean Forest where people never know when to start feeding, how much, etc. I wouldn't know how much to add.
[1] I intend to experiment using an ordinary peat moss, like bales sold at the garden center. Mix 65% peat, 35% perlite. Add some amount of dolomite (in addition to what I add to my mix. I.e., Pro-Mix HP has some dolomite already. I'm not sure how much. The plain peat at the garden center doesn't.). And some myco. (Pro-Mix HP has myco.). I've been told this might not end up being as good as Pro-Mix HP. But... I'd like to find out.
[2] I also use calcitic lime to improve the Ca:Mg ratio of dolomitic lime. Maybe 7/8 Tbsp dolomitic to 5/8 Tbsp calcitic. A 3:1 ratio of those two limes produces a 2:1 ratio of elemental Ca:Mg. (A 1:1 ratio of those limes produces a 3:4 ratio of Ca:Mg.). Anywhere in that range is good. But, dolomite by itself is fine. It's 1.62:1 by itself. That's not optimal.
[3] This was more of a concern when I planted seeds directly in the soil. I still germinate in the soil, but I create a small (1 rounded Tbsp) "seed bed" in the top of the soil. I soak Jiffy pellets in water, cut them open and keep the fine peat material without the netting holding it together. I put some perlite in a plastic bag and step on it a few times to break the perlite chunks down to a sand/powder consistency. I add that to the fine peat. Maybe 1:1 or 2:1 peat to perlite.
I feel like the Jiffy pellets are too dense and dry too slowly. Also, the net interferes with the roots. But, I also feel my soil is too chunky for sprouting. So, I scoop out a Tbsp or two of my soil, and replace that depression with fine peat & perlite material.
This is a photo of it in wet soil & seed bed (the seed is in the center, hasn't been covered yet). You can't see the finer, more-powdery perlite mixed into that fine peat. It's about 1" diameter and 3/4" deep:
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