Soil mix for indoor-baggie rose rooting vs. outdoor rooting with rain
Above is a rooting from cutting done outdoor, with tons of rain of Geranium red in 1/3 perlite, 1/3 potting soil, 1/3 coarse sand, plus tons of holes drilled on the pot. It was wimpy until I put in full-sun and it became twice taller. Rooting cuttings outdoor is best with sun, more sun = faster growth (as reported by Kitty Belandez blog in CA).
Indoor rooting with baggie-method (totally enclosed) is more challenging in my zone 5a. I keep my indoor temp. at 65 F, so root-growth is very slow. After 3-weeks with at least a dozen baggies with different soil mix ..... The best performance is a pop-bottle over a band-size-container (mostly opened at bottom). That sprouted new leaves !! That has coco-coir, sand, perlite, plus 1/2 potting soil.
The worst baggie is with Cheryl Netter's method of 1/2 potting soil plus 1/2 perlite, plus pouring 1/4 to 1/2 cup water down the stem. That was too wet, and leaves are yellowish after 3 weeks. Just too much water accumulated !!
The best baggie, using those zippered pouch that hold bed-sheets .. is with Fafard cactus soil, only $5 for a big bag at local grocery store like Aldi & Woodman's. It's a slightly acidic & sterile soil, with granite sand (rich in potassium and phosphorus.
After 3 weeks, all cuttings in this Farfard cactus potting soil RETAIN green leaves & no leaf-loss nor yellowing, inside a closed baggie. I slightly wet this medium, and DID NOT POUR any water down the stem.
Farfard catus and succulent potting mix is good stuff. When I poured it out, it's completely dry & fluffy and loose, cannot find a single clump !! In contrast, MG-potting soil is mostly Canadian brown peatmoss ... so dense that I had to use 2 steel scoop to cut through. Folks reported mold and gnats inside MG-potting soil.
Since cactus prefer a pH of 6.5 to 5, this mix is perfect for rooting roses.
Also I put my baggies in a few hours of sunlight so molds don't grow. Sunlight kills mold. Recently I pulled many cuttings from outdoor, the darker the soil, the longer the root. With more sand, the less rooting ... that works for both rain or no-rain.
Certain roses like sandy/loamy soi, those are the ones that Val (hot & sandy Florida) reported as doing well for her: polyantha, Austin Heritage & Jude, China, Tea.
But Austin roses definitely need black & humus rich soil to root. Golden Celebration was easily rooted in 1/4 black clay, 1/4 sand, and 1/2 potting soil, plus red-lava rock .. a rich & dense & wet medium.
Sphagnum peat moss, black earth (humus), sand, perlite, lime, fertilizer
GUARANTEED MINIMUM ANALYSIS
Total Nitrogen (N) - 0.04%
Available Phosphoric Acid (P2O5) - 0.01%
Soluble Potash (K2O) - 0.08%
Maximum Moisture - 18%
Organic Matter - 21% - See more at: http://www.fafard.ca/en/produit/cactus_and_succulent_plant_potting_mix/#sthash.31iISYWm.dpuf