My Old Mix
I've been using a base mix containing 90% #3 coarse perlite and 10% peat moss (Sunshine, fwiw.) The perlite was cooked for two days in a tea (more recently an FPJ) containing beneficials, high P bat guano, crab meal, humic acid and cold-pressed kelp w/ a solution pH of 5.8. Liquid is strained out from perlite, filtered and used later. The peat moss gets the same treatment w/ the addition of a mineral tea containing Sulfate of Potash and Oyster Shell Lime to get a balance of K and additional micros into the mix as well as to raise the pH. I usually let the mix settle for at least 3 das and give it a stir or two before taking a final pH reading and making adjustments as necessary. The finished product is a light, airy substrate w/ a balanced nute and bio-beneficial menu that gets transplants off to a good start. (My starter mix is similar, but uses 20% medium perlite that I merely cull out of the #3 coarse bag to simplify things.)
During the plant's lifetime the lion's share of it's nutrition comes from liquid compost teas. With this system, the plant is fed hydroponically at first, but by mid-term the tea residue has filled in the substrate and to look at the medium's properties, one would never know that what they're seeing in the containers had been 90% perlite a few weeks earlier.
Old Mix Advantages
1) light weight
2) highly absorbent- expands <-> gains weight w/ watering, very little runoff, virtually no tunneling or dry pockets
3) O2 friendly- one would have to work extra hard to compress and lock the O2 out of this medium.
4) responsive. w/o the buffering properties of a typical mix, it is easier to adjust for deficiencies and respond to the plant's changing needs during specific stages of development.
Disadvantages of Perlite Based Mediums
1) perlite is not a particularly environmental friendly mineral product
2) under some circumstances, perlite can present a security problem
3) dust. requires a mask when working w/ it in it's dry state but the major problem is the inevitable excess of dust that shows up in the air and floor of the grow rooms over time.
4) water use. Count on watering every day beginning a week after they've been flipped to flower.
5) high maintenance- laborious and time consuming. (see 2, 3 and 4)
There might be more to say or something I missed but that's a fairly accurate description of what I'm moving away from now that I just finished off the last of my perlite and all but the last cu ft of peat moss.
My Proposed New Container Mix
Base Materials:
Coco Coir - PV's (contract packaged) brand. They use it in their custom mixes. I trust it.
Rice Hulls- sustainable, eco friendly, aesthetically pleasing replacement for perlite. (PV)
Arctic Humus
Pumice
Soft Rock Phosphate
Glacial Rock Dust
Crab Shell Meal (Also mixed into hole prior to transplant)
Oyster Shell Lime
Drench Brew-
(for moistening, watering in and dispersal of soluble nutes/bios throughout medium.)
endos & bacilli
CP kelp
molasses
sulfate of potash
- mixed into a concentrated tea- brewed 2 days @ 80F and diluted w/ warm, ROd water before application.
- soluble endos in weak CP kelp solution applied to roots and mixed w/ crab shell meal to inoculate surface around transplant hole @ each of the 3 transplant phases.
- For 4" -> 1gal and 1 gal -> 3 gal, soluble, hydroluzed fish powder @ regular strength added to the drench to supply readily avail. N and create a good macro balance in the mix for vegetative growth phase.
Notes:
1) I purposely didn't set base material ratios as I will be bracketing them for a run or two to find the happiest mix for the plants. Beginning Coir : RH ratios w/ other ingredients remaining @ constant 20% (ie coir/RH : other materials = 8:2
- coir : RH : other 5 : 3 : 2; 4 : 4 : 2; 6 : 2 : 2
2) worm castings used in teas. have avoided wc's in mix due to tendency to "clog up" and stratify in my perlite based substrate. my opinion may change w/ new substrate.
3) bat guano has been my P work horse during flowering- particularly during mid- final. I am veering away from guano, due in large part to the info I've picked up from from various folks here at the organic boards, (you know who you are.) I'm not going to cut it completely out, however. I still haven't found a better nute for getting a sweet, strong nose to the buds so will cut back overall use and pull out for the last couple of P feedings.
4) used pumice extensively along w/ decomposed granite, pea gravel and a few other amendments in terracing and xeriscaping my old house- natives, cacti, euphorbias, succulents etc. This thread got it back on the radar, so why not?
Thanks to all of the contributors. My new mix would be quite different w/o having the solutions and advice that have been provided here.
This is still a work in progress. Constructive criticism is never a threat to me nor will it burst my bubble.
I may have overlooked something or could have likely made a change or two by the time you are reading this so... don't be bashful w/ the comments.
Peace
GG
