Time to get pots set for winter
Best to throw out nutrient depleted soil
What to do with containers, now that fall has arrived?
One of the questions I am asked most often is whether to keep this year’s used potting soil to reuse next year. You should not reuse the mix, because this combination of mostly peat moss and maybe some compost and/or perlite is very poor in nutrients.
While perfect for use on balconies because it’s so light, this kind of soil doesn’t last long because most of the nutrients get used up during one growing season. It can also harbour diseases, so it’s best to throw it out at the end of the season.
Speaking of next spring, when it finally does arrive, you may want to consider using some water retaining crystals in your mix. Many readers complain that their containers dry out so very quickly on hot summer days, and by mixing these crystals into your potting mix, you can cut your watering back considerably. The crystals work by retaining water, thereby reducing watering frequency.
The other thing to consider is not to skimp on the quality of the potting mix. Some of the poorer mixes contain sticks and twigs and their sterility is questionable. If you are on a budget and don’t want to pay for the more pricey mixes, try making your own potting mix. Mix one part sphagnum peat moss, one part vermiculite and two parts compost (sifted if possible).
This will be far more nutrient-rich than the typical mix you can buy, which usually contains only peat moss and a little vermiculite.
If you’re planning to bring plants indoors to overwinter, remember there are many insects that live in the soil of outdoor containerized plants and even more who hide very well in the leaves. A very good idea before bringing any plant indoors is to treat them with an insecticide such as Doktor Doom House and Garden or Ambush. Spray the top of the soil and the leaves, making sure you get as much spray under the leaves as possible.
If you are overwintering a containerized plant outdoors, wrap the container with an insulator such as Fiberglas home insulation, the more the better. This will help protect against freezing and thawing. The insulation should be added not only around the sides of the container but also on the bottom. I would also recommend keeping the plant in a sheltered, shady location. Placing it out in the sun increases the chances of thawing, and protecting it from drying winter winds is crucial.
Another problem to contend with is the moisture factor. The soil should have some moisture in it to keep the roots from drying out completely and yet too much moisture can create problems with ceramic or terra cotta pots. The expansion of the water as it freezes can crack non-plastic containers and even some plastic ones. Check the soil regularly for moisture. If it feels dry, water lightly.