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pro mix all purpose for seed starting marijuana

Premier Tech Pro BX? If so it has everything but soil really. Macros, micros, beneficial mycorrizhae for kick ass root growth. Do you need soil?

You definitely go that route Bethany420. However it’s much more work in my opinion. Soil additives will make your life much easier.
I’m not aware of anything that can be added to water though to improve drainage.


maybe next year i will add some perlite and lime to a couple of pots and see if it adds any benfeit for me.

1 3.8 cf bag of Pro Mix BX or HP
1 cf of compost (earth worm castings, thermo compost)
.5 cf of perlite, coco shells, pumice or rice hulls
6 cups of Espoma brand bio tone starter plus
3 cups alfalfa meal
3 cups kelp meal
3 cups crab meal (Neptune harvest)
2 cups of a 50/50 mix of Neem cake and Karanja cake ( This stuff is amazing but expensive.
Minerals as follows 1 cups of soft rock phosphate (or brown rock), 1 cup of crushed oyster shells, 1 cup gypsum 3/4 cup of sul po mag, 1 cup of azomite
Mix it thoroughly on a large tarp or cement mixer.

I’m using Pro-mix HP. I add extra perlite, dolomite lime and Worm Castings.

Lance Lawnson
Horticulture Specialist
US-West, Canada-West

JoAnn Peery
Horticulture Specialist
US-Central, Canada-Central

Once in use, it generally lasts about one to two weeks, depending on the rate the manufacturer incorporates, how much water is applied to plants (volume divided by frequency) and plant uptake. If you are unsure of the fertilizer content, check with the growing media manufacturer for fertility levels. Some growers prefer to water in with a water-soluble fertilizer immediately after planting with about 100 ppm of nitrogen, while others prefer to wait a few weeks. This is a personal preference. However, if you water in immediately, you should adjust the fertilizer level of the growing media. This will account for any imbalances or loss of nutrients in the growing media as a result of product aging.

9. Algae may form on the top of the growing media

Product aging begins the day the growing media is manufactured. Most manufacturers print a manufacturing date on the package. If you use packaged growing media, check with the manufacturer for this date. If you mix your own, keep records for the day you mixed it. The best use of a typical packaged peat-based growing media is 8 to 9 months during the summer months and 10 to 12 months through colder, winter months.

Troy Buechel
Horticulture Specialist
US-North East

Sometimes there are a lot of weeds in greenhouses. Growers often blame the growing media, but sphagnum peat moss has few, if any, possible weed seeds.

The most difficult change to overcome is the water requirements. Select a growing media that has similar watering characteristics to what is currently being used. Having the same appearance when it dries out is also ideal, as many growers use the color of the growing media to determine when to water.