Since we’re filling our growing containers, let’s talk about how we deal with storing our container garden soil over the winter! This is a major component of operating a container garden cost effectively!
Since we have a sizable container garden, we had to scale our soil storage fairly high. We use what are called Geobins to store our soil, which are basically some inexpensive, low-tech and heavy duty composters. Each Geobin can hold around 250 gallons of soil and we have two dedicated to soil storage. We might need to add a third as our soil storage needs continue to grow. (We also use them for actual composting, too!)
We really like this solution as it heavily promotes cold composting of the roots over the winter months. While a considerable amount of roots go into the Geobins, very little comes out when we re-use the soil the next season. Just like with composting, the outer edges don’t compost all that well, but the inner stuff does. Nonetheless, it’s fairly easy to separate the soil from roots once they’ve gone through the winter.
At a smaller scale, you can certainly use things like Rubbermaid containers to store your soil. We did this for a lot of years, prior to scaling up our storage needs to several hundred gallons. The composting won’t work quite as effectively in these smaller containers, since you need a fairly large mass to promote composting. But, it’ll still work decently enough. You can even just make a pile in your yard somewhere, we’d recommend putting down a tarp or weed fabric.
The main drawback to this method is that the soil never fully thaws by the time we need it in late May. We often get a “soil iceberg” in the bottom, even after a month of temperatures above freezing. Once its exposed, it does thaw fairly quickly, but we often have to get somewhat creative with our timing of things. It’s a very northern problem, for sure.
If you want to “refresh” the soil, it’s usually a good idea to shovel the soil into another vessel, like a wheelbarrow. Here you can infuse things like compost, granular fertilizers or additional amendments. We occasionally do this, but not necessarily every season. A lot of our soil is basically treated like a hydroponic medium, given our use of sub irrigation and fertigation techniques, so our “soil health” isn’t of paramount importance in most cases.
We’ve been reusing our soil in our container gardens for many, many years. We think concerns over things like disease are somewhat overblown. We do practice common sense, though, and wouldn’t recycle soil that clearly had a diseased plant. Also, we fairly naturally get a good “crop rotation” each year, just by changing the soil instead of where the plants grow.
Some people do just leave their soil in their growing containers. We generally disagree with this practice, except for very large growing containers like whiskey barrels, since the root structures in containers become quite substantial. Also, for us, we just don’t have the space to store that many containers full of soil. Having our container garden break down into a small space for winter storage is important for us.
So, if you’re not re-using your soil, hopefully this gives you a bit of insight into how you can! Lastly, we did put together a video on this topic last year, so you’ll find that down in the comments, should you long for more!
