Q: What can I do to prepare my garden for winter? Right now it’s 100 degrees, but I want to know what to do when the weather finally cools off.
Nobody wants to work in the garden when it’s super hot outside, but you can get some small tasks done in the early morning or evening. First, remember that extreme heat is stressful for plants, so whatever you can do to minimize this stress will be helpful. Plants experiencing duress will attract pest insects and arthropods through chemical signals. Under these conditions, pests can quickly get out of hand, so watch for signs of damage such as dull or rough-looking leaves (mites), sticky leaves and/or the presence of ants (aphids or scale), damaged or missing leaves (caterpillars). Sometimes these can be managed by simply spraying off leaves with a jet of water from a garden hose. Use caution when applying pesticides since some will damage plants when used above a certain temperature. Always read the label directions for guidance.
Annuals, including vegetables, can be removed at the end of their season. Determinate varieties of tomatoes (Roma-type) likely have already produced their crop and can definitely be removed. Indeterminate tomatoes may still produce, but they can be cut back to keep them manageable. When pruning indeterminates, remove any brown, withered branches. Then, starting from the bottom, remove any branches that don’t have flowers or tomatoes. Discard any damaged fruit and fallen leaves since leaf litter can harbor insect eggs and cocoons. If you live in a frost-free (or relatively frost-free) area, you can end up harvesting tomatoes into the new year.
Most perennials will tolerate some pruning at this time. Some natives (sages and lavender) will develop a dense, woody base that can be unsightly. Prune these plants by removing some of the woody stems at the base. Then you can clip the top growth to encourage dense regrowth in the spring.
Tree pruning should wait until dormancy (when all of the leaves have fallen). Trees with a dense canopy can benefit from moderate pruning that opens up the canopy and allows wind to pass through. Heavy pruning to reshape the tree should wait until the tree is asleep for the winter.
Use a rake to pull out dead leaves from the base of any plantings since this is where many insect eggs hide. Basic cleanup activities like this can be done over the course of several days with just one or two hours of work in the morning or evening.
Los Angeles County
mglosangeleshelpline@ucdavis.edu; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/
Orange County
ucceocmghotline@ucanr.edu; http://mgorange.ucanr.edu/
Riverside County
anrmgriverside@ucanr.edu; 951-955-0170; https://ucanr.edu/sites/RiversideMG/
San Bernardino County
mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu