What potting soil recipes, materials and ratios, do you use in your gardens or farms? Specifically, what on-site materials do you use? I am trying to get a sense of local materials I can use in my own garden and to recommend for others.
I am an outdoor and garden educator and the author of The School Garden Curriculum: An Integrated K-8 Guide to Discovering Science, Ecology, and Whole-Systems Thinking. Inspired by ecological design and permaculture principles, my goal is to make weekly gardening lessons more easily accessible to all educators and to inspire the next generation of change-makers.
I have a local company that processes seaweed, and in doing so, they use a lot of Perlite. Their waste product is thus a seaweed/perlite compost that I can buy at a reasonable, $1.90 a ton. So I use some of that, then I get soil out of my forest. I like soil from a forest because it has a lot of microbes in it from the constant mix of forest litter, and soil, so it ends up being black dirt...really good stuff. It is a pain though because I do have to screen it to get the rocks and crap out of it. I then add aged manure from my sheep farm.
With add all three to my cement mixer and just let it churn. If you do not have one, you might consider it, I use my cement mixer for mixing stuff besides concrete, and washing stuff in bulk as well. You can get cheap, decent ones at Harbor Freight for very little money. (Just a thought).
As for ratios: I am not sure, but I would say probably 1/2 a 5 gallon bucket of that seaweed compost, then 2 buckets of soil, to 1 bucket of sheep manure.
Is this the best starting soil mix? No idea, but it is what I use, and it seems to grow things quite well.
I make my potting soil in the wheelbarrow. It holds 3.5 cubit feet of soil when full.
1/3 sharp sand or decomposed granite (for drainage)
1/3 fresh compost (for microbial life and carbon)
1/3 garden soil from right out in the orchard—I pull back the wood chip mulch and scoop up the rich soil below.
I'll throw in a big handful of azomite (to mineralize it) and any chicken manure that's available. If I have it, I'll add a 5-gal pail of composted steer manure. Chicken manure is pretty hot, so a little goes a long way.
Mix with a shovel.
Sand is usually available on the outside curve of any river. You've just got to get down in the water with a shovel and dig it up. If I have none available, decomposed granite also provides great drainage. After the winter is over, there are always sand bags laying around. I'll grab them and repurpose the sand/DG that's in them to make potting soil.
This mix has a lot of organic material in it to hold water and feed the microbial life. It's filled with microbes from the compost and the garden soil. It drains well, while still remaining adequately moist -- something of an ironic combo.
I start most of my plants in old red Solo cups (with a hole drilled in the bottom), and then transplant them either into 1 gallon pots, or directly into the soil, depending upon the plant and the season.
In a normal garden season, I'll make at least 3 batches of soil like this --- about a cubic yard.
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf
My potting mix is 1/3 sharp sand (I have a lot of blasting sand left over from a project) 1/3 composted stall and coop clean out manures and 1/6 regular compost (leaves, grass, twigs, pulled up vegetable stems) and 1/6 soil from my forest area, to this mix I add 1 cup of sea-90 for complete mineral availability for the microbiome that is in my mix.
Currently I mix by hand but we will be getting a cement mixer (like travis I love the idea of being able to mix without elbow grease or back breaking hoe work) it will make it easier to use this same mix for raised garden bed top off.
I always put a 1.5 inch layer of large pea gravel in the bottom of the containers or I make the container a wicking container.
I use the above mix for planting just about everything that is going into a container after it has sprouted and set the first set of true leaves.
I filled a large pot with just leaf mulch- decades old because the previous owner never touched beneath the old tree. The grape vine I planted in the pot is thriving and into its third year now.
I had way too much clay soil and nothing else. I filled containers with it and planted seeds anyway. Some plants do well in it, like scallions and basil, whilst others don’t. It gets really dry and contracts in summer, but very tough plants manage to survive. Not recommendef but it’s good enough for some leafy plants.
It also has way to much information on soil as well.
You can substitute what you have for similar ingredients. Such as compost and leaf molds etc.
Soil & Recipe
A basic super soil recipe. Understanding soil mineralization, soil ecosystem and brix in general will help you appreciate this recipe.
This soil is capable of lush growth and bountiful yields. It is tried and tested via years of use.
Recipe list: 1-large bag (2 cu ft) organic potting soil. (no added fertilizers)
Add compost of mushroom, leaf mold and/or forest humus and/or ocean compost if soils do not contain.
Best practice is to add a blend of all.
Compost is carbon and is vital to your PH and micro life stability.
1-large bag (2 cu ft) light mix (hanging basket mixes)
1 cu ft perlite or comparative drainage product (choose a brand)
1 cu ft worm dirt (worm castings) or (cow manure-composted)
2 cup bone meal (Alternative = soft-rock phosphate alternative)
2 cup blood meal (Alternative - alfalfa meal)
3 cup Kelp meal (I do not add to mix as I input during grow regular but this is normal part of recipe)
4 cups fruit bat guano
1 cup dolomite lime,
1/2 cup Epsom salts
Can use agricultural lime but increase Epsom salts to 3/4 cup from the 1/2 cup Epsom salts
Biochar - you can inoculate with any below or any nitrogen based solution with microlife.
Inoculate with natural farming inputs high in nitrogen.
Inoculate with equal amounts of garden teas and molasses.
+Pest management and brix additives.
BTI (gnat control)
Nematodes (optional pest control for most soil based bugs)
Rock dusts & azomite
Myco fungus and bacteria.
Break Down of Recipe
1-large bag (2 cu ft) organic potting
Any organic potting soil soil with good drainage.
You want soil with a mix of humus and ocean blends.
No chemical fertilizers
If you cannot find, add in the following type of composts
compost with ocean shells and kelp.
compost with good humus and or mushroom compost.
1-large bag (2 cu ft) light mix type of potting soil.
Fox Farms Light Warrior soil, or promix or media for hanging baskets, or orchid mix it is likely suitable.
Any high drainage potting soil or soiless media
no chemical or additional fertilizers.
1 cu ft perlite (choose a brand) Rice hulls are also good, biochar will do similar if used and if so perlite could be skipped.
chunky and not so fine.
High drainage is key for getting air to roots.
Some of the biggest indoor plants I have seen, were grown in only perlite.
I dont recommend only growing in perlite.
1 cu ft worm worm castings, (Cow Manure, composted is a very good alternative and some would say that about worm castings).
Add this in, in addition to any worm casting that might be contained in the other soils, you cannot have enough really.
This is key to jump starting the mineralization process.
Source of microbes and is where the bio life will mostly come from.
Watering in with a garden/compost/casting tea will help boost microbes too.
Generically I use basic veg tea without adding nitrogen other than castings and composts (my compost has some nitrogen from worm bin drainage)
You can adjust for the growth of the plants, using nitrogen aspects in vegetative periods and phosphorous when in flowering phases, generically spoken.
you will not burn your plants with correct castings.
Take it easy with worm bin drainage this is hot hot hot.
If you use your own castings you will see the sprouts of what you eat will come up initially when soil is put in grow room/container. I let this happen for a moment as it helps jump start the microbe life in soil.
The sprouts of stuff gets recycled in compost bin but also can be used for making an IMO to help boost sprouts similar to roots excelsior. I will write on that later.
1 cu ft compost (optional).
If only able to get basic soil and basic light mix
Add compost with sea minerals
Add compost with humus
Garden or home compost
Bokashi is a very good alternative for garden compost).
2 cup bone meal NPK - 3-15-0
This adds phosphorous.
(Alternative = soft-rock phosphate alternative)
Add fungi mycorrhiza as it breaks down the phosphorus and makes it available to the plant.
Plants can only get phosphorus from bone meal if the soil PH is below 7.0 (acidic soil). (I have never seen as issue but if phosphorous is an issue than check PH out out due diligence.
2 cup blood meal NPK - 12-0-0
Add nitrogen and can be made into a liquid
(Alternative - alfalfa meal)
I like for recharging soil
helps maintain compost
A single application of blood meal is usually effective for 6 to 8 weeks before subsequent feedings are needed.
Is quick acting and can burn your plants if you use too much.
Take it easy adding extra nitrogen to your recipe.
If young plants show a bit to high ec signs, reduce blood meal in the recipe by a 1/4 to a 1/3 next time.
It is easier to add than take away. If you have light feeding plants use less and adjust accordingly listening to the plants.
Blood Meal works with bacteria and nematodes (worm castings and teas are typical source) in the soil to breakdown the powder into nitrogen components so plants can more easily absorb the nutrients.
4 cups fruit bat guano NPK 0-10-0 (NPK can vary but ensure higher in P than N)
adds NPK but also adds mico life like worm castings
Reduce and increase as per your plants feeding. Reduce for light feeders but I would not increase without getting a feel for the soil and how it works with your plants.
Guano helps keep the soil loose and not bulky by aiding decomposition
This helps keep a good aeration at the roots.
1 cup dolomite lime
You can also use agricultural lime or garden lime but you might need to adjust the magnesium.
If using agriculture lime than increase Epsom salts by 1/4 cup per gallon which adjusts the magnesium.
1/2 cup Epsom salts
Magnesium is absorbed right when the seed begins to develop.
Magnesium assists with the process of seed germination, helping to strengthen the plant cell walls and improves received nutrients.
Magnesium assist with making chlorophyll
Magnesium helps the plant take in phosphorus and nitrogen
Sulfate, a mineral form of sulfur.
Sulfate is essential to the health and longevity of plants, and aides in the production of chlorophyll.
It works like a catalyst in the soil to make key nutrients more effective for plants, including nitrogen, phosphorus and potassium.
2 cups of rock dust
(many do not do this, it is not needed but will increase brix if activated/mineralized by biolife) .
Adds trace nutrients and macro nutrients.
Needs to be mineralized to work (biolife)
2 cups of Azomite
(many do not do this, it is not needed but will increase brix if activated/mineralized by biolife)
Similar to rock dust
I like as it breaks down differently than rock dust.
BTI, Mosquito dunks to chunks to liquid.
Sprinkle bti on the soil and mix real good.
Liquid drops (microlift) (a few drops will take care of 30 gallons of water)
work faster than dunks
Use yucca when watering to help even spread in medias.
Great protection for fungas gnats.
It will not prevent infection but prevent them from reproducing.
Using these will prevent infestations
Some of these ambush and some actively hunt. Horror movie monsters in miniature.
Hope that helps.
Living free starts with understanding ones own emotions and emotion affects and controls us.
Potting mix I use: Compost, Worm Castings, Coconut Coir (soaked), some soil from the garden. Add sand if I've got any available.
Coconut coir comes in three types: compressed, chipped, fibre.
Compressed blocks - put in a wheelbarrow and soaked in a lot of water. I add a few cups of seaweed/fish emulsion for a kick along. Stir with a garden folk and after leaving it an hour or so it breaks down into a fine, water holding medium.
Chipped - good for orchids and mulch around pot plants.
Fibre - typically formed into cup shapes for hanging basket liners.
It's good stuff because it retains water and has a few other beneficial properties.
'Every time I learn something new, it pushes some old stuff out of my brain.'
I'm experimenting with a completely different thing based on my hunch that sawdust can be "charged" similarly to biochar. Since I have access to a ton of fresh sawdust and shavings from a friend who has a business making furniture and such, and the chickens aren't here yet (the rabbit/chicken house isn't finished yet), I'm working to get it's benefits into the hard, depleted, clay soil here.
Here's how I do it . . . 2 scoops of sawdust, 1 scoop goat manure. 2 scoops sawdust, 1 scoop charcoal powder/ash mix, 2 scoops sawdust, 1 scoop local soil (best I can find), 2 scoops sawdust, 1 scoop compost (if available, 2 scoops sawdust, 1 scoop whatever other nutrient-rich stuff I have. I just keep layering in this rather unscientific formula into a cracked 5 gallon bucket until it's full, topping with a sprinkling if soil to keep it in place. Then pour some water on it. Later, throw some coffee in (I boil my coffee in a pan and then when I rinse the grounds out of the pan, I put the water into this mix sometimes, or directly over where I buried kitchen waste last . . .). When I make pasta or rice or boil potatoes or whatever, I throw the water in the bucket. I pour pee in too. And I think I'll start pouring in some sea salt water to add minerals. I've also thrown in chicken blood and ground up eggshells. I can throw in some of my worm castings too. Once I get my weed
/compost/anarobic sludge barrel going, I'll throw in some of that. Sugar water or a bit of dilluted molasses would likely be beneficial as well. Beer too. Flour or other ground grains in moderation.
I don't put in any food scraps at this point. I burry them a and later will use for my bunnies and the black soldier flies I feed to the chicks.
Cover with a grain sack to keep it dark and mostly moist. After a few days to a week, dump it into the sack. Continue to add random liquids so it's always moist. Every couple of days, kick the sack around so it gets mixed and aerated a bit.
I figure it's useable pretty quickly, though more time might be better. Within 2 weeks, I end up with a gorgeous, dark, flaky, rich, earthy smelling, constantly moist material that is beautiful for planting in. I've only been doing this recently, so we'll see, but I suspect it's going to be a real winner.
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