Gardeners are an inquisitive bunch, but the thing about our questions is that most other people have them, too.
Here’s an assortment of questions we received but didn’t have time to answer during our recent Gardening 101 webinar. You can view the recording, where we answered a lot of other questions, here, and sign up for the next webinar, Gardening in Small Spaces with author and landscape designer Susan Morrison, at www.mercurynews.com/events or www.eastbaytimes.com/events.
Q. When is the best time to spray peach and nectarine trees for peach leaf curl?
A. Two applications are recommended. The first before the tree starts putting on leaves, which is usually in January or February. And again after the leaves have fallen, usually in November.
Q. Does it matter if you spray and your neighbors don’t?
A. Peach leaf curl is caused by an airborne fungus, but if you spray your trees as directed, then any fungus that blows in from your neighbors shouldn’t affect your trees.
Q. What is the master gardeners program and is it open for anyone to join?
A. California’s Master Gardener program is a public service and outreach program under the University of California Agriculture and Natural Resources, administered locally by participating UC Cooperative Extension county offices. It was founded in 1980 and uses a cadre of trained volunteers.
Training is offered once a year. Training classes were cancelled in 2020-21, and the 2021-22 class remains up in the air. Contact your county’s master gardener program for information. Websites are listed below.
Q. Do you recommend thinning as a way to produce more yield?
Thinning is a difficult thing to do — emotionally, not physically. But it’s necessary so that you give plants the room they need to grow strong and produce. Plants and fruits crowded too close together compete for limited resources and space. As a result, they don’t grow as robust as they could.
Q. Should you use the online farmer’s almanac for planting?
A. Sure, that’s a good resource. Just be sure to use the guide for your specific planting zone.
A. I’ve read that white vinegar with a little dish soap is a good non-toxic weed killer. Is that true and what about its impact on soil?
A. A mixture of vinegar, salt and dish soap can be used as a weed killer. The dish soap acts as a binder and the salt and acetic acid in the vinegar cause the leaves to dry out and eventually die.
However, this mixture only kills the above ground portion of the weed so, depending on the weed, you still may need to pull the roots out. Be careful not to get the mixture on plants you want to keep.
Using household vinegar, with a typical 5 percent acetic acid level, should not harm your soil. Agricultural vinegars have a 20 percent acetic acid level and can be harmful to microbial life in soil as well as lizards, frogs and other animals.
Q. Do you have a preference between raised beds and in-ground gardens? Also what is the best way to keep gophers out of the garden?
A. For those of us with creaky joints and bad knees, raised beds can make the physical chore of gardening a little better, but you can grow in-ground or in raised beds just the same. To keep gophers out of raised beds, attach hardware cloth, a type of metal grid, to the bottom before filling with soil.
If you have a serious issue with gophers in your in-ground beds, you might need to plant in gopher cages that keep the gophers from reaching the plants.
Q. I’ve read that aphids don’t like bananas. Is this true? Would it help to dig chopped up banana peel into the soil around my milkweed and green onions, which were infested by aphids last year?
A. I doubt very much that the aphids will be bothered by banana peels, but they might attract rats or raccoons. Instead, just wash the aphids off your green onions with water.
The oleander aphid is a common pest on milkweed. Again, spraying with water will help reduce the population. The best solution is to provide plenty of habitat for beneficial and predator insects that feed on pests. An example would be to grow an array of lavender, rosemary, salvias, yarrow and borage.
Q. Is it good to leave leaves beneath a fig tree?
A. Generally yes. You can leave them unless the leaves show signs of insects, such as scale or spider mites.
Q. When you buy plants to transplant, there are often 2 plants right together. Do you plant them together, or separately?
A. Generally, you can divide them carefully and plant them separately. Some plants, such as cucumbers, don’t like to have their roots disturbed so clipping of the smaller seedling and planting the larger is a better way to go.
Q. How do you learn to estimate how much to plant? Like for a family of two, how many zucchini or green beans? Is there a resource to help me estimate yield?
A. That, of course, depends on how much you like various vegetables, what percentage of your diet comes from those vegetables and whether you intend to preserve any of your harvest.
In my family of two people, two zucchini plants are enough, but 50 bush bean plants are just a start, and 15 to 20 tomato plants give us plenty for eating and for canning. There are plenty of resources on line to help you get started, here are a couple: https://harvesttotable.com/vegetable_crop_yields_plants_p/ and a vegetable calculator.
Q. Is a 12-inch raised bed enough? I’ve seen ads promoting 15-inch, 24-inch or 36-inch tall raised beds.
A. It’s all a matter of preference and price. A 12-inch deep bed is plenty deep enough, as the plant roots will go deep into the soil beneath the bed. The taller beds make it a little easier to tend the garden without having to bend too much. The width of the bed, from front to back, should be no more than 4 feet across in raised beds or in-ground beds, making it easy to reach the center of the bed from either side.
Q. Marin is Zone 10a but it seems it’s warmer than that. How strictly should I follow the sone recommendation?
A. Use the zones as a guide but know that the Bay Area boasts many microclimates.
Q. My husband is a woodturner, and there is always lots of sawdust from his work. Can this be used? Is there any type of wood that should not be used?
A. Sawdust is an excellent source of carbon and can be used in compost, much like dry leaves, using a 4:1 ratio of carbon (brown) to nitrogen (green.) Any type of wood is fine, although you may want to avoid too much eucalyptus. Do not use any chemically-treated wood.
Q. The soil in one of my raised bed has too much nitrogen (lots of foliage, very little fruit). How do I get rid of it?
Q. Before doing anything, you should test your soil with a small, inexpensive home gardener test kit or a commercial test to determine what the nutrient levels are. There may be other reasons for too much foliage and little fruit, such as not enough sun or not enough pollinators.
If it turns out you do have excess nitrogen, grow plants that require a lot of it, such as squash, corn, broccoli and cauliflower, will help with the problem.
Q. Do you have a favorite book or online resource you recommend for a very inexperienced gardener?
A. Try “The Vegetable Gardener’s Bible” by Edward C. Smith. I also like the “Western Garden Book of Edibles: The Complete A-Z Guide to Growing Your Own Vegetables, Herbs and Fruits” by the editors of Sunset Magazine.
Q. Do you recommend that we save some of our copious amounts of leaves for using as mulch later in the summer? I never thought about saving the leaves and have always put them in the green bin.
A. By the time summer rolls around, your leaves will likely have broken down into compost, so they aren’t as effective as a mulch. Using them right away, even on beds with nothing planted in them, is a better plan.
Q. Do you recommend using Epsom salts or crushed egg shells in preparing soil?
A. Epsom salt can be added to soil as a magnesium source, but should not be added without first testing the soil to be certain of a deficiency.
Crushed egg shells can be added to the soil as a calcium source, but because they take so long to break down and become available to the soil, they are best composted first.
Check out these other Q&As:
Master Gardener county websites
Alameda, acmg.ucanr.edu/
Contra Costa, ccmg.ucanr.edu/
Marin, marinmg.ucanr.edu/
San Mateo and San Francisco, smsf-mastergardeners.ucanr.edu/
Santa Clara, mgsantaclara.ucanr.edu/
Solano, solanomg.ucanr.edu/
Monterey and Santa Cruz, mbmg.ucanr.edu/
Check the Master Gardeners website in your area for information on upcoming spring plant sales. The Master Gardeners also maintain help desks to answer your questions by phone.
