Hi,
I am going to need more potting mix. But rather than going and buying pre-made bags I figure I could make my own instead since it might be cheaper. I already have a 3 cu bale of Sphagnum peat moss. What other ingredients could I use to make a good potting mix? I am going to be growing tomatoes, peppers, some herbs perhaps, and maybe even strawberries.
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PunkRotten
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I LIKE PEAT MOSS especially mixed with strained garden soil.Today I planted 15 boxes of seeds in my greenhouse. The bottom of the box is strained garden soil with some shredded paper at the bottom. I tap it down and add about a inch of starined potting or peat moss with some sand mixed in. I tap it down and add the seeds and top it with spagham and potting mixed with sand and tap it down and cover with a window till they come up! You can do the same thing with any container> The straining gets most of root weeds out.+++++++
+++ The several inches of mixed weedless soils on top stops the weeds. You c an even add a thin layer of paper top the garden soil which stops weed seeds but the seedlings you are growing will root through the paper as it gets wet! hope this helps. River sand or bought sand works great . Some river sand has weed seeds in it! I used play sand!
+++ The several inches of mixed weedless soils on top stops the weeds. You c an even add a thin layer of paper top the garden soil which stops weed seeds but the seedlings you are growing will root through the paper as it gets wet! hope this helps. River sand or bought sand works great . Some river sand has weed seeds in it! I used play sand!
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rainbowgardener
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Basically with your peat moss (or coconut coir) you want something organic for fertility and something to keep it loose and well drained.
Organic could be compost, mushroom compost, worm castings, etc.
Drainage would usually be coarse sand and/or perlite.
I will soon be making my own potting soil for the first time. Coconut coir, mushroom compost, worm castings, and perlite is what I am going with.
Organic could be compost, mushroom compost, worm castings, etc.
Drainage would usually be coarse sand and/or perlite.
I will soon be making my own potting soil for the first time. Coconut coir, mushroom compost, worm castings, and perlite is what I am going with.
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PunkRotten
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applestar
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One basic formula is 2 parts peat moss, 2 parts garden soil, 1 part perlite. Which is 1/5 or 20% perlite.
I tend to prefer about 1/4 or 25% sand. Haven't used perlite in a while so I'm not sure if you can get away with less % perlite.
I just bought a 5 lb block of compressed coir that I'm mixing with premium (Dr. Earth) potting mix and sand with worm compost tea to make soil blocker mix for seed starting, but, usually, what I do is mix about 2 parts 1/2" screened under the wood/leafpile top soil, 1 part 1/2" screened compost, and 1 part sand for seed starting, and add rock phosphate, greensand, lime (if higher pH is needed) and reconstituted alfalfa pellets (more nitrogen) for uppotting. I increase the sand to about 1/3 of the mix for cactus, rosemary, lavender, etc.
For large containers, I use unscreened compost and topsoil for larger aggregate size -- better drainage.
I tend to prefer about 1/4 or 25% sand. Haven't used perlite in a while so I'm not sure if you can get away with less % perlite.
I just bought a 5 lb block of compressed coir that I'm mixing with premium (Dr. Earth) potting mix and sand with worm compost tea to make soil blocker mix for seed starting, but, usually, what I do is mix about 2 parts 1/2" screened under the wood/leafpile top soil, 1 part 1/2" screened compost, and 1 part sand for seed starting, and add rock phosphate, greensand, lime (if higher pH is needed) and reconstituted alfalfa pellets (more nitrogen) for uppotting. I increase the sand to about 1/3 of the mix for cactus, rosemary, lavender, etc.
For large containers, I use unscreened compost and topsoil for larger aggregate size -- better drainage.
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PunkRotten
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You guys mean garden soil right not potting soil? I picked up another bag of perlite so now I have 16 quarts. I bought a bag of 2 cu potting soil and two bags of 2 cu garden soil. I don;t have too much complete compost but I can add little half shovelfuls to seed the potting mix. I have azomite and granular fertilizers like 10-10-10 and the other is like 6-7-4 or something like that.
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applestar
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If you don't have access to good garden/top soil in your own garden, then you could buy inexpensive potting soil -- the kind that is usualy too heavy to use by itself and sometimes contains some soil -- or you could buy better quality top soil, which is what (I think) they scrape off farm property before building a new development housing project (they then layer a bare, thin excuse of what passes for soil just enough to support lawn grass).
We call better -- use more-or-less straight out of the bag -- kind potting "mix" because usually, they are typically soilless, meaning they contain peat (or hopefully coir), compost, amendments, vermiculite and perlite, but no soil.
...Ah, I see, they actually sell them called "garden" soil. Yes, I believe that would work. I'm guessing those are to be perceived for building garden beds? What do they contain? Does it say on the bag?
The key here is that -- I think -- you want to introduce good soil food web in the container -- for me, that includes macro organisms as well as micro organisms. If you are using sterilized commercial/bagged soil, you will definitely need to add compost or worm casting with active microorganisms and/or mycorrhyzae. I believe mushroom compost is a good addition in that respect, though I tend to have some concerns about what chemicals they might use in a commercial, not organic, operation.
The key to container mix is good drainage. Using too much clay in the mix (depends on composition of soil) can cause that. If the aggregate is too fine, they can compress over time. Thats why I don't use very small screen to separate out the big stuff in the compost and garden soil unless it's for seed starting. Depending on what the plant is, and the size of the container, you may want to consider using
- larger grade/size perlite (inert/neutral/airspace/holds moisture and fertilizer), small chip or shredded composted bark (composted small chip pine bark would be perfect for blueberries)
- larger grade/size diatomaceous earth
- pumice stone gravel
- fine gravel, or rough sand (I don't know what else to call it -- The kind I use is Step 2 paver underlayment which contain what looks like crushed stone chips, gavel, and sand)
Adding -- or leaving the drain hole with entry access for -- earthworms can compensate for some of the compressed/compacted soil in containers. Some people duct tape piece of window screen to the inside to block the drain holes so slugs and other undesirables don't get in, though slugs will sometimes still hide just on the inside of the drain hole in the gap between the screen and the container. I put my containers directly on the ungrouted brick patio and in on the ground, and earthworm's always find their way in. I have to add them to the containers for the winter indoor containers for new uppots.
I think of azomite as kind of like greensand -- I.e. I resist buying azomite which I consider to be Rockies region sourced, and try to buy more locally sourced greensand (I might consider crushed granite dust from New England states as an alternative). Use a small amount to boost trace minerals. There is probably instructions on the granular fertilizers on how much to add to new container soil for larger plants. You don't want to add those heavy hitters in seed starting mix and not too much even in the seedling uppot mix.
We call better -- use more-or-less straight out of the bag -- kind potting "mix" because usually, they are typically soilless, meaning they contain peat (or hopefully coir), compost, amendments, vermiculite and perlite, but no soil.
...Ah, I see, they actually sell them called "garden" soil. Yes, I believe that would work. I'm guessing those are to be perceived for building garden beds? What do they contain? Does it say on the bag?
The key here is that -- I think -- you want to introduce good soil food web in the container -- for me, that includes macro organisms as well as micro organisms. If you are using sterilized commercial/bagged soil, you will definitely need to add compost or worm casting with active microorganisms and/or mycorrhyzae. I believe mushroom compost is a good addition in that respect, though I tend to have some concerns about what chemicals they might use in a commercial, not organic, operation.
The key to container mix is good drainage. Using too much clay in the mix (depends on composition of soil) can cause that. If the aggregate is too fine, they can compress over time. Thats why I don't use very small screen to separate out the big stuff in the compost and garden soil unless it's for seed starting. Depending on what the plant is, and the size of the container, you may want to consider using
- larger grade/size perlite (inert/neutral/airspace/holds moisture and fertilizer), small chip or shredded composted bark (composted small chip pine bark would be perfect for blueberries)
- larger grade/size diatomaceous earth
- pumice stone gravel
- fine gravel, or rough sand (I don't know what else to call it -- The kind I use is Step 2 paver underlayment which contain what looks like crushed stone chips, gavel, and sand)
Adding -- or leaving the drain hole with entry access for -- earthworms can compensate for some of the compressed/compacted soil in containers. Some people duct tape piece of window screen to the inside to block the drain holes so slugs and other undesirables don't get in, though slugs will sometimes still hide just on the inside of the drain hole in the gap between the screen and the container. I put my containers directly on the ungrouted brick patio and in on the ground, and earthworm's always find their way in. I have to add them to the containers for the winter indoor containers for new uppots.
I think of azomite as kind of like greensand -- I.e. I resist buying azomite which I consider to be Rockies region sourced, and try to buy more locally sourced greensand (I might consider crushed granite dust from New England states as an alternative). Use a small amount to boost trace minerals. There is probably instructions on the granular fertilizers on how much to add to new container soil for larger plants. You don't want to add those heavy hitters in seed starting mix and not too much even in the seedling uppot mix.
Some people do like to add topsoil to their potting mix, but it should not be clay soil.
I am heavy handed on watering so I use this mix for most of my potted plants. This works as a year long mix. In summer, I have to water daily. But when the rains come, I have less problems with rot.
50% peat 50% perlite = peatlite plus osmocote (slow release fertilizer)
For a mix that holds more water = 4 parts perlite, 2 parts compost, 4 parts peat moss, 1/4 part grow power or topsoil, plus osmocote.
In pots, aeration is key. Perlite is expensive. If you don't mind the weight, you can use sharp sand instead.
Grow power contains humic acids. I have clay soil. If I add clay soil to my potting mix, it just gets heavy and contracts from the sides of the pots too much.
Containers only get the nutrition that is added to it. Slow release fertilizers in sterile mixes are good for starting seeds and carrying plants through the first year.
I supplement with water soluble fertilizer, fish emulsion, vermicast or compost tea depending on what I have and the time of the year. You could leave out the slow release and just do the compost teas or fish emulsion instead as long as you don't have neighbors nearby.
I am heavy handed on watering so I use this mix for most of my potted plants. This works as a year long mix. In summer, I have to water daily. But when the rains come, I have less problems with rot.
50% peat 50% perlite = peatlite plus osmocote (slow release fertilizer)
For a mix that holds more water = 4 parts perlite, 2 parts compost, 4 parts peat moss, 1/4 part grow power or topsoil, plus osmocote.
In pots, aeration is key. Perlite is expensive. If you don't mind the weight, you can use sharp sand instead.
Grow power contains humic acids. I have clay soil. If I add clay soil to my potting mix, it just gets heavy and contracts from the sides of the pots too much.
Containers only get the nutrition that is added to it. Slow release fertilizers in sterile mixes are good for starting seeds and carrying plants through the first year.
I supplement with water soluble fertilizer, fish emulsion, vermicast or compost tea depending on what I have and the time of the year. You could leave out the slow release and just do the compost teas or fish emulsion instead as long as you don't have neighbors nearby.
Good garden soil mixed with anyhing you buy is the key! Where I have some good soil in the garden I scrap the top 4 inches off in lets say a 6 by6 area and take about 6 inches of the under soil for all my mixes. usually
+++I buy potting soils and spagham or composted manure and mix them. In large containers I usually put a few closed empty water bottles in the bottom of the container then cover with dirt. I also like styrofoam for the flower contaiers for the bottom!I also add leaves or shredded paper to the botom! The bottles make the container lighter and help with drainage . I have several big containers that weigh over 50 pounds full of dirt but with the bottles I maycut the weight by 10 pounds!
+++I buy potting soils and spagham or composted manure and mix them. In large containers I usually put a few closed empty water bottles in the bottom of the container then cover with dirt. I also like styrofoam for the flower contaiers for the bottom!I also add leaves or shredded paper to the botom! The bottles make the container lighter and help with drainage . I have several big containers that weigh over 50 pounds full of dirt but with the bottles I maycut the weight by 10 pounds!
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rainbowgardener
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Personally, I think drainage is the key for containers and even more so for seeds or seedlings. My garden soil is too dense and moisture holding to add to anything. In containers that plants are going to be in long term, garden soil tends to keep compacting over time, eventually turning in to a brick. I know applestar adds earthworms to her containers, to help keep aerating the soil. Adding some bark chips, small twigs, etc (for long term plant containers, not for seeds/ seedlings), can help maintain some air/ drainage channels.
Worm castings in a pot is too fine. I'd rather use home made compost as a topping for nutrients and adding " organic microbes: for a sterile media.
I normally use fir bark fines, some peat or coir, perlite or pumice, a dash of turface and Fox farms happy frog or ocean forest potting soil or EB Stones Edna's ultimate ( nice myco's)
and dash of gypsum for ca, mag and your favorite organic fert. Neptunes Harvest. fish /kelp for liquid amendments with touch of vinegar to balance the ph.
Avoid compaction, too moist retention and keep the airation and good moisture retention. It all on the the particle size !!
I normally use fir bark fines, some peat or coir, perlite or pumice, a dash of turface and Fox farms happy frog or ocean forest potting soil or EB Stones Edna's ultimate ( nice myco's)
and dash of gypsum for ca, mag and your favorite organic fert. Neptunes Harvest. fish /kelp for liquid amendments with touch of vinegar to balance the ph. Avoid compaction, too moist retention and keep the airation and good moisture retention. It all on the the particle size !!
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rainbowgardener
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I just mixed up homemade potting soil for the first time. I eyeballed it, not measuring, but it is roughly 2 parts coconut coir hydrated, 2 parts mushroom compost, 1 part perlite, 1 part worm castings, with a few earthworms mixed in.
It is seeming a bit heavier and wetter than the potting soil I am used to. I will let it sit for awhile and see what happens, perhaps add a bit more coir and perlite....
Once I decide it is ready, I will do the experiment. I have some cabbage seedlings already potted up in MG potting soil and more cabbage seedlings from the same batch waiting to be potted up. I will put them in the homemade stuff and see which do better!
It is seeming a bit heavier and wetter than the potting soil I am used to. I will let it sit for awhile and see what happens, perhaps add a bit more coir and perlite....
Once I decide it is ready, I will do the experiment. I have some cabbage seedlings already potted up in MG potting soil and more cabbage seedlings from the same batch waiting to be potted up. I will put them in the homemade stuff and see which do better!
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UrbanGardenDiva
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A lot of times the mix I use depends on the type of pot I have, what I am planting and how long it is going to be in the pot.
For general planting on plants that I am going to keep year round, I use 50/50 mix of peat moss and perlite + osmocote. I need to water daily in summer, but I have fewer problems with rot in the rainy season. This is the mix I will use for seedlings and most of the vegetables and plants that I will keep in pots for a couple of years max.
I plant citrus trees in 20 inch pots in pure black cinder. They need very good drainage, and I have not had to repot any trees in cinder. On the down side, they need to be fertilized regularly and watered every couple of days. The pots are heavy so they are not moved. I have trees that are 15 years old in the pots and the pots still drain well. When I plant citrus in any other media, I need to repot them every three years or when they outgrow the pots, and I sometimes have problems with the rootball being dry in the center after watering.
Cactus and succulents do best in clay pots that breathe. 40%peat moss, 60% perlite or cinder and peat moss.
I have red clay soil. Clay expands and contracts. It pulls away from the sides of the pot and drains very slowly. If I add it to the potting mix. It will be for something like water lilies or taro since the plants like to be submerged in water and the clay covered with stones will stay together better.
I have not had good results using compost in pots, except for vermicast tea or a handful of vermicast added to 5 gallons of peat lite.
Even with 20% compost in the mix, I will have problems with the pots holding too much water and slow drainage.
Orchids do best in baskets with hapuu or cinder. I have been trying to switch to orchid bark, but I find it hard to plant and unforgiving about repotting as the media breaks down and the orchids rot. Hapuu is still the best but getting harder to find and they sell mostly crushed cinder now, so it is difficult to find cinder in larger sizes.
For general planting on plants that I am going to keep year round, I use 50/50 mix of peat moss and perlite + osmocote. I need to water daily in summer, but I have fewer problems with rot in the rainy season. This is the mix I will use for seedlings and most of the vegetables and plants that I will keep in pots for a couple of years max.
I plant citrus trees in 20 inch pots in pure black cinder. They need very good drainage, and I have not had to repot any trees in cinder. On the down side, they need to be fertilized regularly and watered every couple of days. The pots are heavy so they are not moved. I have trees that are 15 years old in the pots and the pots still drain well. When I plant citrus in any other media, I need to repot them every three years or when they outgrow the pots, and I sometimes have problems with the rootball being dry in the center after watering.
Cactus and succulents do best in clay pots that breathe. 40%peat moss, 60% perlite or cinder and peat moss.
I have red clay soil. Clay expands and contracts. It pulls away from the sides of the pot and drains very slowly. If I add it to the potting mix. It will be for something like water lilies or taro since the plants like to be submerged in water and the clay covered with stones will stay together better.
I have not had good results using compost in pots, except for vermicast tea or a handful of vermicast added to 5 gallons of peat lite.
Even with 20% compost in the mix, I will have problems with the pots holding too much water and slow drainage.
Orchids do best in baskets with hapuu or cinder. I have been trying to switch to orchid bark, but I find it hard to plant and unforgiving about repotting as the media breaks down and the orchids rot. Hapuu is still the best but getting harder to find and they sell mostly crushed cinder now, so it is difficult to find cinder in larger sizes.
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ElizabethB
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This spring I have been re potting all of my potted plants - herbs and ornamental plants.. I have a LOT. Some needed to be potted up to larger pots, some needed to be divided and ALL needed the soil refreshed. Anyway - mixed my existing soil 1/2 soil from the pots and 1/2 compost. Plants are smiling. I still have a huge plumeria to repot - it is actually 2 plants so 2 pots and an enormous boston fern that needs to be divided into 6 or 8 pots and 2 asparagus ferns that will divide into 3 or 4 plants each. Well my compost is running low and these plants are so root bound that there is little or no soil. I added 1/3 peat and 1/3 course vermiculite to my compost. I will toss in what little soil I retrieve from the pots. That is my recipe - 1/3 compost, 1/3 peat, 1/3 vermiculite. Good for my pots and good for beds and garden.
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PunkRotten
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rainbowgardener
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Garden soil is really too heavy and dense for containers. Probably a little is ok if well mixed with other ingredients.
1/3 peat, 1/3 compost, 1/3 perlite is the Mel's mix recommended for square foot gardening. Besides the sustainability issues I have mentioned, I think 1/3 perlite is a lot. I've been making my home made potting soil, 2 parts coconut coir (peat substitute), 2 parts mushroom compost and 1 part perlite, which makes it about 1/5 perlite. Seems adequate to me.
1/3 peat, 1/3 compost, 1/3 perlite is the Mel's mix recommended for square foot gardening. Besides the sustainability issues I have mentioned, I think 1/3 perlite is a lot. I've been making my home made potting soil, 2 parts coconut coir (peat substitute), 2 parts mushroom compost and 1 part perlite, which makes it about 1/5 perlite. Seems adequate to me.
this is what I normally use if I make it myself ...
1/4 forest topsoil (find a nearby forest and use some of the topsoil, but not if it is acidic (pine trees etc)
1/4 perlite
1/8 worm castings (vermicompost)
1/8 peat moss
1/8 well rotted farmyard manure
1/8 homemade well rotted compost
a handful or two of volcanic rock dust
then, feed regulary with AACT, seaweed extract, fish extract etc
1/4 forest topsoil (find a nearby forest and use some of the topsoil, but not if it is acidic (pine trees etc)
1/4 perlite
1/8 worm castings (vermicompost)
1/8 peat moss
1/8 well rotted farmyard manure
1/8 homemade well rotted compost
a handful or two of volcanic rock dust
then, feed regulary with AACT, seaweed extract, fish extract etc
I do my Whatever Mix. For the most part, start with bagged stuff. For containers mixed in a deep cart, or if small amount in 5 gal bucket. If in the bed just pour contents from bags, no measure, just guessing.
Top soil. I get a cheap one that has dirt, forest product and sand.
Manure (mix) manure, forest product, sand, not sure (hard to overdo with stuff other than poo)
Cotton burr compost
Soil conditioner - forest product
Worm stuff, if I have it (my fellow vendor at the farmers market has it fresh by the 5 gal bucket)
Compost, (mine is a mix)
Not all of these in every batch, just whatever is there and try to keep a balance of dirt and organic.
Depending on what is going in the container goes heavier or lighter on richness.
I will say if pots coming in, such as basil coming in for fall, use MG or Fafards mix.
Top soil. I get a cheap one that has dirt, forest product and sand.
Manure (mix) manure, forest product, sand, not sure (hard to overdo with stuff other than poo)
Cotton burr compost
Soil conditioner - forest product
Worm stuff, if I have it (my fellow vendor at the farmers market has it fresh by the 5 gal bucket)
Compost, (mine is a mix)
Not all of these in every batch, just whatever is there and try to keep a balance of dirt and organic.
Depending on what is going in the container goes heavier or lighter on richness.
I will say if pots coming in, such as basil coming in for fall, use MG or Fafards mix.