Mulch is an organic, inorganic, or synthetic material that we place on the surface of the soil. Even though organic mulch will eventually decompose if left in place, unlike compost and other soil amendments, it is not meant to be mixed into the soil. Mulch has a valuable role to play in the garden, but should you use mulch around potted plants?
There is no doubt that potted plants can benefit from mulch, especially those planted in large containers. Mulching potted plants is a great way to conserve soil moisture and protect the roots of any potted plant. If you use natural, organic materials, these will break down and add nutrients to the soil. Some synthetic materials will add a decorative touch.
Is it necessary to mulch potted plants?
It’s a good idea to mulch around potted plants but it’s not essential unless you’re into container gardening in a big way. After all, it’s easy enough to control weeds, maintain consistent soil temperatures, and ensure that a handful of potted plants stay healthy.
But there are benefits of adding mulch around plants in pots that are definitely worth considering.
Benefits of mulching potted plants
Anne Sawyer, extension educator at the University of Minnesota Extension emphasizes the importance of watering and fertilizing container plants. She also believes that mulch is very good for container gardening.
The most important role of mulch in containers, she says, is that it helps to minimize water loss from evaporation. Mulching potted plants also moderates the temperature of the soil surface which helps to keep the roots of pot plants cool in hot summer weather.
The right sort of mulch will prevent potting soil from splashing out onto the leaves of plants when you water. This is important because as Sawyer says, this kind of splash can easily spread plant pathogens from the soil to the plants. For example, it is known to be a problem with tomato plants.
We know that mulch is an excellent tool in helping to prevent weeds from germinating in containers. But it can also minimize plant spread if you spread mulch too close to plants. This is why we say it’s best to use mulch in larger containers so it doesn’t cramp the plants.
It stands to reason that the value of most organic mulches will be negated if you are growing annuals. This is because it won’t have time to break down and produce nutrients.
Instead, if you choose to use decorative-type mulches, you can scoop them up and rinse them off to use again.
Suitable Types of Mulch for Potted Plants
Sawyer’s top choice for potted plant mulch is grass clippings. But they must be free of herbicides.
If you don’t have a garden with lawn or access to grass clippings elsewhere, you can use a little hay or straw instead. But your containers need to be big enough.
Other natural materials that can work include burlap, shredded newspapers, and coconut coir. Master gardeners and extension specialists at the University of New Hampshire detail a greater selection of mulch materials in a Garden Mulches fact sheet.
Organic types include shredded hardwood, leaves, pine needles, aged sawdust, pebbles, stone chips, and gravel. Synthetic materials like black plastic and landscape cloth are unsuitable for mulching potted plants.
Other sources suggest decorative glass, marbles, polished pebbles, clay balls, wood chips, pecan shells, and moss. Polished semi-precious stones or granite chips can also look gorgeous.
How do you mulch a potted plant?
Generally, if you are using natural mulches, apply these when the plants are established. Don’t allow the mulch to come into contact with plant stems otherwise they might rot.
A good rule of thumb when mulching plants in the garden is to use a layer that is about two to four inches thick. However, if you are using mulches of shredded leaves or grass clippings it shouldn’t be deeper than two inches otherwise it will restrict air supply and water.
When mulching potted plants, your mulch shouldn’t be more than about one or two inches thick. If you’re using any type of decorative glass, pebbles, or stones, don’t use more than a single layer.
Whatever type of mulch you use, you need to spread it over the topsoil. It’s that simple. Just be sure to leave a gap about one to two inches thick from the stem.
Useful tips when mulching plants
One of the problems people have when mulching plants in containers is that the mulch prevents water from reaching the soil. Even if it just slows down the flow of water, this can be detrimental.
If your houseplants start wilting despite regular watering, check the moisture of the soil under the mulch. It shouldn’t be dry. And if the mulch is sodden, then you’ve also got a problem.
The solution, though, is easy. Either way, remove some or all of the mulch.
Another useful tip is to avoid anything that may contain weed seeds. Hay and even grass clippings are two examples.
You can prevent weeds from germinating in your containers if you let fresh mulch sit for a few months before you use it. If weeds sprout, pull them out of your developing mulch and dispose of them.
And here’s some food for thought. Leaf litter attracts beneficial insects and butterflies.
Leaves are a free, natural resource that you can use to mulch garden beds and potted plants. When using leaves for container gardening, it’s best to shred them first, for practical and aesthetic reasons.
Mulching potted plants can have some great benefits, as long as you don’t use too much mulch. You want to avoid smothering the soil so that water can’t penetrate and air won’t circulate.
Generally, mulching works best in larger-sized containers. It is also more effective if you don’t have plants that are going to spread as they grow.
There are lots of mulch-type choices. Consider them carefully and apply less rather than more.