Soil For Container Gardening
Real soil from the garden compacts under the pressure of repeated waterings. It literally turns into concrete and then your tender plant roots will not be able to grow. Not grow much – but grow at all. Your plant growth will simply stop and along with it all flowering or fruiting.
So, we use an artificial soil and I don’t mean a bagged topsoil, miracle soil, super soil or a bagged potting soil. Those still contain too much soil and/or sand and will compact.
I mean a peat based artificial soil that are based on peat moss. They often contain perlite to increase the drainage or vermiculite to do the same thing on a short term basis. They often contain a small “charge” of fertilizer that will get your plants started but only for the first week; after that all feeding is up to you. They will also contain a wetting agent that will allow you to easily wet the mix and have water penetrate.
Fill from Top to Bottom with Peat Soil
You use this soil to fill your container from top to bottom. No pebbles or clay shards are needed in the bottom of the pot to “improve” drainage.
This improving drainage canard is an old wive’s tale. Your soil for container gardening will and must drain properly if you fill the pot from top to bottom with the same mix.
I’m experimenting with straight peat moss mixes because I have too many large containers and I use a significant amount of soil every year. (My Scottish ancestry means I’m always looking for inexpensive but effective gardening techniques) I’ve found that if I use peat moss mixed up to 30% *good* compost, then I get an excellent product and the plants grow quite nicely. Bagged manure is not good compost but it did work quite nicely when mixed at 15-25% of the mix. As a soil for container gardening, the manure worked but not as good as compost.
Straight peat moss also grows an excellent container plant although it is slightly harder to get wet at first and you need to pay attention to feeding and watering more than with an artificial mix.
Caution with Container Growing and How to Fix It
With all the peat mixes, it is important NOT to let them dry out. Your watering must be regular and when the plant requires it. The disadvantage of any peat mix is that you’ll have the devil’s own time trying to rewet a dried out peat soil and the plant will be the worse for wear.
What You Can Grow in These Artificial Soils for Container Gardening
Annuals, herbs, and perennials can easily be grown in this kind of soil
If you are growing larger trees or shrubs in containers, it will pay you to go to a nursery and purchase some of their “nursery mix”. This is a very porous bark mix that will not compact very quickly and you’ll get several years from each repotting. Nurseries use this soil for container gardening with large plants to avoid having to transplant every year.
Never Use it For This Plant Class
And finally, if you are growing water garden plants in containers, feel free to use the heaviest garden clay soil you can find. You’ll be much happier with the performance of this than any artificial soil. You simply can’t use a peat based soil (dry peat floats!) and anything containing perlite will leave a ton of little white beads floating on the water surface.
Click here to ask about soil for container gardening.