How to make your own Potting Mix
The weather this winter has been horrible. We’ve been buried in snow most of the time. I normally like to get some winter gardening projects done to get a jump on spring, but that just hasn’t been possible. I like to start some of my annual vegetables in my greenhouse towards the end of February for the cool season plants, and towards the end of March for the warm season plants. With some above freezing weather, I was finally able to thaw out some compost to make my potting mix.
I’ve tried quite a few different potting mixes for my transplants. I’ve purchased pre-made potting mix, which worked fine, but was terribly expensive. I’ve tried using mostly compost, with just the top inch or so being the potting mix. This was much cheaper, but the results were not as good. I’ve tried just using compost from the garden, but my germination rate was spotty at best. This year, I’ve decided to make my own potting mix, so I can get the good results, without the high cost.
What’s in potting mix? (Mix these by volume)
3 parts peat moss
1 part compost
1 part perlite
1/3 part topsoil
How to Make the Potting Mix
1. Gather up your materials. I purchased a 3.8 cubic foot cube of compressed peat moss, a 2 cubic foot bag of perlite, (3) 50 lb. bags of compost, and (1) 50 lb. bag of topsoil. This was enough material to make about 200 gallon sized pots for about $50 in material cost. In the future, I will use my own compost. I had to buy it, because my pile was frozen.
2. I used a large wheelbarrow to mix the materials. I put about a third of the bale of peat moss, a third of the bag of perlite, a third of the bag of topsoil and one bag of compost into the wheelbarrow. Then I mixed it with a shovel, and broke up all the clumps by hand. The peat moss was very dry. If peat moss is below 30% moisture content, it will be hydrophobic, which means no matter how much you water your pots, it will simply repel the water. I Mixed each batch of potting soil with a few gallons of warm water mixed with a couple of drops of dish soap to break the surface tension. This got the peat moss wet enough to soak up the water. Do this before putting the mix into pots.
3. I set up a lawn chair next to the wheelbarrow, and scooped the potting mix into my ½ gallon sized pots. This was easy, relaxing work, that didn’t take too long or waste much material. Whatever fell on my garage floor, I swept up and put back in the mix.
Was it actually cheaper?
It cost me $50 to make (200) ½ gallon pots, or (100) gallons of mix. If I purchased a large high quality potting mix, it would run me about $17 per (64) quarts, or (16) gallons. Converted to (100) gallons would be about $106.25. So there is a substantial savings of $55 or so. I could also save an additional $10 by using my own compost in the mix.