You may be asking “whose mix”? Mel Bartholemew is the author of All New Square Foot Gardening and the founder of the square foot gardening method. He recommends filling your garden boxes with a special mix, instead of dirt. Here’s the mix and the benefits:
- 1/3 vermiculite
- 1/3 peat moss
- 1/3 compost (from as many sources as possible)
This is done by volume. My garden beds were each 4′x4′ and needed 6″ of mix to fill them. 4x4x.5=8 cubic feet of Mel’s mix. I did three boxes, so I needed 24 cubic feet of mix, 8 cubic feet of each item. Now, this amount did fill my boxes initially, but as I watered and the mix settled, I added more compost.
Why not just use dirt? You can, but there are some great benefits to Mel’s mix:
- Planting and germination –Mel’s mix is much lighter than dirt, and it doesn’t get compacted down because you never walk on it. This allows seeds to push through much easier, so you don’t have to be so particular about what depth you plant the seeds.
- Root systems –It’s really easy for roots to grow and spread in Mel’s mix. I was surprised when I pulled up my lettuce plants, the root ball was so large, nearly the whole square came up with it. I just shook out the mix and composted the old plants.
- Weeds –WHAT WEEDS! As long as you are careful with what compost
you get, there are no weed seeds in your mix (unlike dirt). If a seed blows in,
the mix is so loose it’s easy to tug them right out. Again, I spent less than 1%
of my time in the garden weeding.
- Drainage –with Mel’s mix, you cannot over water! Mel recommends hand watering, but if you choose to irrigate, how do you get the right amount of water to each plant? Easy!
use a drip system, and watered away! Mel’s mix drains so well, you don’t have to worry about it.
When you use Mel’s mix, you don’t have to worry about what kind of soil you have, or amending the soil. Every time you plant a square, you add a trowel of compost. You don’t have to rotate where crops are planted, or do anything special, unless you want to.
Mixing It Up–Tarp Method
Mel recommends mixing this on a tarp– It might work to combine 1m3 at a time.
- Pour compost on a large tarp. If you used several types, mix it following the instructions below before adding other materials.
- Add vermiculite.
- Add peat moss.
- If it’s really dry and dusty, mist it down but do not get it wet (makes it heavier).
- Mix by taking two corners of the tarp and pulling them over the tarp (like making a burrito) until all the material is close to one edge, lay the tarp flat. Then take the opposite two corners and pull the other direction, lay the tarp flat. Switch back to the other side and pull until all material is running down the middle of the tarp.
- Now shift 90 degrees (so you are looking down the column of material) and repeat. Basically, pull north, then south, then north until it’s in the middle. Then pull east, then west, then east until it’s in the middle again. Repeat until it is uniformly mixed.