My current best practices for running my 10 outdoor veggie SIPs for two years, and my current indoor 420 run, is to either plant seed directly into a SIP that has a 1/4-1/3-full SIP reservoir, or start in a small grow bag first. To direct-sew water seed in once, but only once as this reduces overall moisture level but preserves the moisture gradient, and do not refill reservoir past 1/3 full at least before Nodes 3 -5 have grown. A cloche can be deployed if you struggle to maintain above 65% RH around your large pots. I prevent seedling stretch by having a bright light up in their faces at moment they break soil, but, for this and for other reasons listed below, I do not direct-sew cannabis but rather have developed a SIP-hybrid seedling program I follow.
This is my go-to, most recommended method: I plant germ'd seed into a perforated, non-woven, cloth nursery bag about 4-5 inch diameter and 8 inches deep (you can customize depth by folding down the edge or cutting). Placed in a cup or bowls these can be lightly bottom watered to establish a moisture gradient from day one to ensure a plant's hydrotropic root development response immediately (this simply means that a plant chooses different root types and layouts based on the moisture level at various depths, just as it does in nature where moisture gradients are the norm). This, smaller, "pot" size gives you much more finite control over this moisture gradient and can make it easier to temporarily place your seedlings in ideal high-RH environments if your veg space struggles.
As a breathable cloth pot, these 'mini-smart pots' encourage dendritic root formation - that is, air pruning and subsequent branching off from the pruned root by a new root, as opposed to the constant curling and wrapping undertaken when they meet the plastic borderline of a traditional pot.This has been scientifically been shown to improve plant health, reduce veg times and increase yields. I like how easily this setup can be bottom watered, allowing the plant to take advantage of its genetic disposition favouring a moisture gradient between the pot's wetter bottom and the soil's drier surface, preventing the necessity of growing a root 'ball' with feast or famine traditional container grow methods.
After 3-5 nodes exist, drop the seedling, still in the perforated cloth bag, into ready-made hole in SIP with the reservoir filled no more than 1/2, preferably 1/3 only but if your res is small and you fear it emptying and dry-out before you can next water, a
little extra over 1/3 full should be ok. We want the plant to recognize the moisture gradient of our SIP and such gradients are more pronounced and noticeable to young roots when the reservoir is initially kept under 1/2 full. This is only for a few days to a week. I add my mycs, frass, and fulvic acid, all activated with sprayable beneficial microbes, at the time of transplant. I renew the bennies and fulvic weekly with a small drench two weeks after transplant and every week hence. In my personal experience this has worked better, leading to a larger plant, more quickly than either direct sewing or traditionally watered (draught'n'drown) seedlings.
I can't stop. Gelato-K is a funny strain lol
