Hello and welcome to Part 2 of our how-to series on year round indoor salad gardening.
In today’s post, I’ll discuss how to choose containers, what soil to pick for planting and share a recipe for adding water to soil in the proper ratio to prevent mold from rearing its ugly head. We’ll give you a detailed list of supplies for growing micro greens and show you how to store them in handy-dandy boxes to prevent Supply Sprawl – necessary if you’re growing in a small space like me. (For Part 1 of the series, click on the Year Round Indoor Salad Gardening sub-menu nested under The Resilient Container.)
We’re using the method outlined by Peter Burke in his book, Year-Round Indoor Salad Gardening : How to Grow Nutrient-Dense, Soil-Sprouted Greens in Less Than 10 Days (Vermont, Chelsea Green, 2015). You can read an interview with Peter Burke here.
Burke recommends using disposable 3X6 inch foil trays for planters. He suggests that beginning growers start with the disposable trays then graduate to other containers as they get more familiar with the growing techniques. I decided to use the containers I already had on hand while learning the techniques because didn’t like the waste disposable trays would generate or the ongoing cost of buying new trays.
Since my partner and I are both gardeners, we had all kinds of plant saucers lying around that could easily be re-purposed as micro greens containers.
Our growing collection of food storage containers with no lids were also likely candidates. (Why throw them away?)
These take out containers (plus an old, vintage Tupperware container that used to belong to my mother) were resurrected from the depths of our basement, and given a new life as micro greens containers.
I looked for containers that could hold a minimum of 1 1/2 inches of soil. In addition, the plant saucers, food storage and take out containers were all food safe (#5 plastic). The only one without a food safety marking is the Tupperware container, which is about 40 years old.
After a good scrub in hot, soapy water, the containers were ready for soil and fertilizer.
Burke recommends using an all-purpose potting mix (AKA a ‘soilless’ mix) to grow micro greens. So any potting soil you’re already using in your container garden will work fine here. If you’re a new gardener and are bewildered by the eye-popping plethora of choices, cut out all the noise by picking a potting soil that fits your budget.
Don’t pick one that has added chemical fertilizers or hydration beads or one that has a ton of organic fertilizer added in. Why? Because the plants will only grow for a couple of weeks, max. They don’t need a built-in, three-month supply of slow-release fertilizer.
Instead, we’ll add small amounts of compost (or composted manure) and kelp (in meal or liquid form) to the bottom of each container before adding in the soil. As the roots grow down toward the bottom of the container, they’ll absorb the maximum benefits of the fertilizer.
According to Burke, micro greens grow best when they are planted in potting soil that’s been pre-mixed with a proper ratio of water-to-soil before planting. You don’t want to add a bunch of dry potting soil to your containers and water it in, because soil that is too wet will cause mold to grow on your micro greens. And we don’t want that!
Pre-moistened soil doesn’t come ready mixed in a bag so we have to do this ourselves. Luckily, Burke provides his recipe for the perfect planting mix: 1 gallon of soil (16 cups) to 4 cups of water.
I started out using a spoon but soon discovered that my hands did a better job. I mixed until the soil was uniformly dark. If you plan to plant fairly regularly, you can make this recipe in bulk and bag it up in 1 gallon portions.
After mixing, my soil looked almost black:
I quadrupled Burke’s recipe and stored 2 gallons in a lidded tote. I also filled two sealed bags with 1 gallon of pre-mixed soil each. I’m interested to see which one dries out faster. (I’ll re-post the results later on my Instagram feed.)
Because I plan to reuse my potting soil, I also re-purposed a lidded garbage container (5+ gallons) to compost root-bound soil ‘cakes’ from the micro greens garden, and nothing else. I won’t add in any additional greens like kitchen scraps or browns like shredded paper or leaves. Since I plan to eventually recycle this soil back into the micro greens garden, I don’t want to add in any ingredients that might promote mold.
Burke recommends pushing the soil down as tightly as possible each time the composter is filled, breaking up dried pieces and stuffing them down into the spaces between cakes. Repeat until the composter is full and close the lid. The composter will need to ‘cook’ for a couple of months (or more) before the soil can be reused.
Burke recommends keeping several gallons of pre-mixed soil on hand as well as all the supplies you’ll need to grow your garden. I used an 18 gallon tote to store my supplies.
It fits nicely in between two filing cabinets…
…and the soil box fits perfectly underneath my writing chair.
My list of supplies includes:
-4 gallons of pre-mixed soil
-containers that are at least 1 1/2 inches deep
-a small tarp
-composted sheep manure
-liquid kelp fertilizer
-yogurt containers for soaking seeds
-measuring spoons and cups
-a stack of newspapers (folded over and wet down, these will make ‘lids’ to put over the freshly-planted seeds)
-small watering can with spout
-small pump sprayer
-a pair of scissors
-lidded container for composting
Last month’s splurge really inspired me to cheap out. I re-used old plant saucers for containers, re-purposed leftover potting soil, and used the same fertilizers I normally use in my outdoor container garden (liquid kelp and sheep manure). I collected newspapers from a friend, and scrounged up everything else I needed from around the house.
This month’s total cost? A nice, big ‘zero!’
Now that’s what I’m talking about!
Next month, we’ll cover planting and the various adaptations I’ve made to the method, including successes and failures. Remember, Leonard Cohen once wrote that cracks are how the light gets in.