I have created a few DIY Earthboxes, and have been trying to create a good "recipe" for potting mix. What's your recipe for potting mix? My recipe is not yet tested, but I'll share it anyway. Please let me know if you have any suggestions.
My scoop Is a 5.4 cup storage container.
The following "recipe" will fill an 18 gallon container.
This is equivalent to @ 2 bags of potting mix ($7-9/bag depending on brand)
I think this will fill 1 1/2 DIY EB's
This is the mixture in the first storage container
24 scoops peat moss (38%)
21 scoops compost derived from cow manure (33%)
3 scoops vermiculite (5%)
6 scoops perlite (10%)
9 scoops pine bark (14%)
2 cups of Dolomite lime for each EB.
This message was edited May 22, 2006 10:46 AM
Recipes for soilless potting mix
After mixing quite a bit of my soilless mix, I found out that my husband had gotten me peat hummus instead of peat moss. Can anyone tell me the difference? Will this be alright to use in my EB, or will it be too dense like soil? Thanks
Deborah :)
Did you figure out the cost of your DIY blend? Are you saving money or just getting more mix? That's a lot of work if you're at breakeven. It's pretty easy getting large bags of MG mix at Walleyworld.
hilary
I haven't completely figured this out yet, but I just found a place where I could get bulk bags of vermiculite and perlite. Previously, it might have made me barely break even, but now that I can use more vermiculite and perlite without it costing me a fortune, this may be beneficial. I got some REAL peat moss today, since my husband had mistakenly gotten peat humus. The peat humus doesn't draw the water like peat moss, so that could've had detrimental results had I used that instead of the moss. I'm so glad I was able to find such a great garden supply store - much better than Lowe's!! Also, I noticed that they had the Pro-Mix brand of potting mix, but it looked like they only had 32lbs, rather than 1 1/4 cu. ft. I'm not sure how this compares, but the bag looks smaller and feels much lighter than the MG brand, and others at Lowe's.
Some soils come dry & some come (partially) saturated with water, so weight is an unreliable gauge by which to gauge the value of a soil.
Over the years, I've been involved with helping many people build their own potting soils. A good starting point:
5 parts pine bark
1 part sphagnum peat
1-2 parts perlite
Garden lime
Controlled release fertilizer
Micro-nutrient source
At first glance, I believe your intended mix will hold too much water & too little air.
Al
Thanks Al. I was told that pine bark is not good for vegetables (particularly tomatoes), so I'll have to skip that part. Could you please elaborate on the micro-nutrient source? What am I looking for - an organic fertilizer or something?
Of course, it goes without saying that I will include Dolomite lime and fertilizer, but the actual non-soil mix was what I had been trying to figure out. Well, I finally found a place that offers Vermiculite and Perlite in 4cu. ft. bags, so that saves a LOT of money. I have changed my recipe yet again, and opted to go closer to the one sold by Earthbox.com. I still have quite a bit of compost left over, so until I run out, I will continue to use that. Once that has been depleted, I will increase the other ingredients accordingly.
10 parts sphagnumpeat moss 42%
3 parts composted cow manure 13%
6 parts coarse vermiculite 25%
5 parts coarse perlite 21%
The perlite and vermiculite are excellent for keeping your non-soil aerated, as well as encouraging root growth. They are also beneficial in storing the nutrients for the plant, making them available when needed. Another interesting fact about these two items is that they help to insulate the soil, preventing damage due to extreme weather conditions. I am so glad to have found the store where I was able to get the large bags.
Micronutrient source could be Soluble Trace Element Mix (STEM) or Micromax. Maybe you wouldn't need it with that much manure. In the past, I've used up to 20% manure in some mixes...it makes the mix just plain soggy.
My mixes are for prolonged use (>1 year) in containers for greenhouse plants. I use either pine bark or coconut husk chips with peat in about a 4:1 ratio, with dolomite, Osmacote, and Micromax.
Why is pine bark bad for tomatoes? It it something allelopathic? Is it pH?
My guess is that it brings the PH down when it decomposes. I use shredded hardwood mulch in my beds for that reason.
I don't plan on using the manure for long - just until I run out. My husband had made the mistake of getting peat humus instead of peat moss, so I had to find a way to get through that as well. From what I've read, composted cow manure is just a tiny amount of manure with a lot of peat humus. I've asked him to get some dehydrated cow manure, but he can't seem to find it without the peat humus. I'd like to use the peat humus that we already have, but I don't know what I should do with it.
I've been using a mix based on Al's formula for tomatoes in 15 gallon containers, and they have been growing vigorously since the beginning of April. I can tell the roots are starting to fill the containers because I'm having to water much more frequently.
The trick to using pine bark is finding the right consistancy--that is, small, consistantly sized particles rather than the commonly found pine bark mulch that looks shredded and has big chunks in it. I've found the right stuff labeled as soil conditioner, and I've found it labeled as pine bark mulch. You have to just look around.
I'm using the same formula for a homemade earthbox, as well. I added an extra part peat moss to improve the wicking action, but the pine bark and perlite do a good job of that, too, while maintaining good aeration.
DMD - I've used pine bark as the primary ingredient in soils for years & haven't found a single plant that rebels at its use (of course, I don't use it as the primary ingredient in cacti/succulent mixes). Best of luck to you.
Al