Do you find your potted vegetables dry out way too fast in the heat of the summer sun?
Feeling like your plants are lacking, but want to improve soil health without commercial fertilizers?
Finding yourself watering them once or twice a day?
Afraid to miss a day and have your plants shrivel up and be knocked back?
Here are some simple solutions to improve soil when it comes to growing potted plants.
First off, we need to recognize the problem—moisture retention. The healthier your soil is the better it will be at retaining moisture and creating the right conditions to promote growth. Completely dry soil is dead soil and does not absorb moisture well at all. Many people use potting soil from the garden store for their potted garden, which is usually made mostly from sterile peat and Perlite. Normal ground soil comes with an assortment of organic material that help regulate soil moisture levels. Let’s look at how mother nature tackles this problem organically.
In natural ecosystem soil you can find partly decomposed sticks, feathers, leaves, insects and sometimes even animals. These act as sponges and hold onto moisture longer than straight soil. The presence of this type of material also attracts the organisms that aid with decomposition and improve soil. These ground-dwelling critters dig holes, move soil around, and leave liquid fertilizer, in turn bringing even more moisture to the soil.
Root systems of other plants also act as moisture reservoirs, helping contribute to stable soil moisture. Many plants have roots that drive far down into the soil, pulling water and other helpful nutrients from deeper parts of the ground.
Many garden heirloom varieties have deep root systems, which is one reason they are resilient in drought conditions.
Mycelium (the fungi body of mushrooms) is also a hero when it comes to soil moisture retention. It typically thrives in soil that is not parched and will hold onto moisture longer, helping with moisture maintenance. The mycelium of different fungi often grow around root system of plants creating a mutually beneficial relationship. They have the ability to move nutrients, minerals, and moisture from one organism to the other.
Microorganisms provide a rich environment for life and for cycling nutrients in the soil. If the soil is bone dry many of these will either die off or become inactive.
Remember, potting soil from your local garden centre comes sterile.
Directly on top of the ground in a natural ecosystem you can find all sorts of organic debris such as sticks, leaves, dead grass, bark, etc. This helps with soil moisture in a few ways:
- By covering the soil they block the harsh effect of direct sun, which causes the soil to heat up and moisture to evaporate.
- Organic ground cover acts as a protective layer or mat over the soil, preventing held moisture from escaping it too quickly but allowing water to permeate the ground cover. The more organic material on top, the more moisture in is capable of retaining—to a point, of course. If you have too much ground cover the water can’t reach the soil because the ground cover absorbs it all. Stability is in diversity.
- As mentioned, organic ground cover acts like a sponge and holds onto moisture, slowly releasing it as needed.
- Similar to how organic matter in the soil attracts the presence of decomposers, organic material on top of the soil also attracts the same activity, causing beneficial action to happen in the soil.
There are typically many layers to a healthy ecosystem. All of them provide some level of shade to the ground floor.
This is obvious in a forest but also is very much the case in fields, and other open ecosystems. Any amount of shade provided to the soil will reduce the evaporation of moisture and provoke healthier moisture retention. An open patch of soil in nature does not like to stay exposed and is quickly consumed by plant growth when left on its own.
When weeding a garden you remove annoying weeds that compete for resources, but you are also removing a shade source. I’m not suggesting that you stop weeding your garden, but it is good to be aware of the benefits we remove when weeding. Understanding problems and creating solutions helps to improve soil and creates successful gardening.
There is typically less shade cover in potted plants then ground gardens, which make soil retention more difficult. You generally are also trying to get as much sun exposure as possible if you are growing any type of fruiting plants, which makes it more difficult.
Solutions to improve soil conditions
Now that we understand the problem of moisture retention, let’s look at a few simple ways to improve the soil of potted plants.
- Use or mix organic potting soil with different organic debris and micro organisms into your planting and potting mix. You can do this by mixing your own aged compost—see Easiest Composting Method Ever—with potting soil or by simply collecting organic material from outdoors. Pre-bought mixes such as Super Soil Organic Concentrate can be bought at most garden stores.
- Increase the pot size to allow more moisture to be accessible to your potted plant. The difference between a 2 Gallon (7.6L) pot and 7 gallon (25.5L) pot can be having to water half as often.
- Water plants in the early morning or at night to allow the water to soak into the soil. The moisture will be retained for longer periods before it gets consumed and dries up. If you can set the pots up on a drip system it is easy to put in a automatic water timer. I use the Instapark PWT-07 water timers, which save tons of time and stress.
- Create a ground cover! This is probably one of the easiest and most effective ways to increase moisture retention in potted plants. Don’t have access to your own mulch, leaves, grass cuttings, or aged wood chips? Get creative!
- What food are you already eating? Chop up those banana peels into 1”(2.5cm) pieces and toss them in your potted plants. After a day or two in the sun they will be dried and ideal to help improve soil. Garlic or onion peels are great to use because they spread out and are light in colour, reflecting more sun from hitting the soil. Let some leafy greens go bad in the fridge? Give them a new life covering the soil for your potted tomatoes. Extra potato peels, grape stems, or watermelon rinds? Use them too. Just remember not to be adding too much slop as a cover as it can attract the wrong kinds of pests.