Introduction

Many microgreen growers prefer compressed potting soil because it’s affordable and space-saving. The preferred soil at my farm, Piedmont Microgreens, is Promix BX from Premier. Many of the Promix products come in 3.8 cubic foot (CF) compressed bales, making them ideal for stacking and storage. A compressed and baled potting soil is usually cheaper than loose bags totaling the same volume. This is because compressed bales take up less space on trucks and in stores. The main downside is that you, as the farmer, must break the bale apart and loosen the soil before planting. If you lack a potting machine, like the one we have from Stilt Pro, this task can be slow and hard on your back. So, if you (i) don’t yet own a potting machine for your microgreen farm and (ii) you buy compressed bales of soil, this blog is for you. We’ll show you how to break bales for <$200 and 1/3 of the effort when compared to doing it manually.

What You’ll Need

Home Depot - Grout Mixing Paddle ($18)

Home Depot - 50 gal. Rolling Trash Bin ($79)

Home Depot - 18V Cordless Drill ($69)

Home Depot - Face Mask/Respirator ($12)

Mixing Your Soil & Preparing Your Trays

Many people own a cordless drill, which means you could save a few bucks by not buying a new one. I suggest bringing your drill when you visit Home Depot to check if the grout paddle fits. Otherwise, a 50 gal. bin will be big enough to handle a 3.8 CF bale. The face mask is to protect your airways from the particulate matter in the air when mixing the soil. If airborne particles are bothering your eyes, you can wear eye protection as well.

• Fully charge your drill battery
• Cut open your compressed bale of soil
• Dump the whole bale in your garbage bin
• Put on your respirator
• Grab the drill and insert the grout mixing paddle
• Use one hand to hold the drill and pull the trigger. Use your other hand to stabilize the paddle and guide it throughout the soil
• Mix the first 1/3-1/2 of the bale and then fill a few trays. You won’t be able to reach the bottom to mix the whole bale at once. A 3.8 CF bale should yield about 65 shallow trays of soil
• After mixing and filling trays with the first half of the bale, repeat the process for the second half
• When the garbage bin is almost empty, add another compressed bale and start again

How did we break bales before this method? The main difference is in the use of the drill and grout paddle. We still used a 50 gal. bin to contain the soil, but we used our hands to crush and grind the compressed soil against the inside wall of the bin. Loosening the soil this way meant you had to bend over further and for longer durations. Leaning down further into the bin meant more strain on your back and more particulate matter in your face. Not to mention, the whole process took 3-5x as long because your hands aren’t as efficient as a power tool.

A note on bin selection. I used a 50 gal. rolling garbage bin for two reasons. I wanted it on wheels so I could move it in and out of my garage without difficulty, as we filled trays outside. Second, I was space-limited, so I preferred it to take up less space on the ground. If you have space on the floor, keep a large but shallow tote there. I recommend this HDX tote from Home Depot. Why? If the tote is large enough for a full bale, its wide and shallow design lets you mix everything in one go. You won’t have to break it down in 2-3 sections.

If you want to add a solid fertilizer, like Gaia Greens 4-4-4, you can do this when mixing. Dosing the correct amount of fertilizer is especially easy if you opt for the shallow tote. To find out how much fertilizer to use, check the amount needed per bale of soil. Next, add that amount and mix the entire bale well. Once you break up the chunks and loosen the soil, the fertilizer will be mixed in well.

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