Originally published on February 28, 2018
Author Linda Gilkeson
Master gardener and author Linda Gilkeson has just released the Revised & Expanded 2nd Edition of her best-selling book Backyard Bounty: The Complete Guide to Year-round Gardening in the Pacific Northwest. Linda agreed to answer some of our most pressing gardening questions in the interview below, and chose two winning questions from those submitted in our online contest.
What do you see at the biggest challenge to gardeners in the Pacific Northwest regarding the changing climate?
I think the greater variability in weather resulting from climate change is likely the biggest challenge for all gardeners in the region. For many gardeners, however, the shortage of irrigation water as the dry season gets longer and hotter may eventually become the biggest challenge. Weather extremes at unusual times of year are difficult for plants to cope with: For example, heat waves in early May can cause a lot of leaf damage and kill seedlings outright. Cold snaps unusually early in the fall can injure fruit trees and other plants, while late cold in the spring frosts fruit blossoms and prompts biennial vegetables go to seed prematurely.
For new gardeners, what should they look for when choosing a garden site?
Sun, sun, sun! You can’t grow food crops without full sun exposure in the summer. Lack of sun can be the hardest thing to remedy because shading is usually due to some large object you can’t move: buildings, neighbourhood trees, local mountain tops. Lettuce and leafy greens can manage with a half-day of sun, but other vegetables and fruit must have 6-8 hours (more is better) of direct sunshine in the summer. Once you find the sunniest site, you can fix any other deficiencies. Even if there no soil, that can be remedied by building large planters and filling them with soil; even the poorest soil can be amended with compost and organic fertilizers; where tree roots are encroaching, you can install root barriers or build beds with solid bottoms to keep out the roots.
Gardens need sunlight
What are the benefits to starting your own seeds rather than buying transplants? What are some of the easiest seeds to start with?
The biggest benefit is that you can grow any variety you want to, instead of the few usually available as transplants. Variety names are not provided for transplants so you may not know what to grow next year if the plants were particularly successful (or what not to grow if they were a failure). There are big differences between varieties in how well they handle local weather, soil types and plant diseases. You can also make sure you have the right varieties for the time of year, something that commercial suppliers of transplants to nurseries often get wrong for winter harvest crops. My pet peeve is finding summer broccoli and summer cauliflower varieties being sold as winter crops: I know there will be some very disappointed gardeners.
The easiest seeds to start for most people likely will be cabbage family plants, such as broccoli, cabbage and cauliflower. The key to growing healthy seedlings is being able to provide really bright light during the day, something that most houses do not have. Without enough light, seedlings have long, pale stems and tilt toward the light. Unless you have a bright sunroom or greenhouse, you may need a grow-light setup. While ideal germination temperatures are 21-30oC for all vegetables, once seeds have come up, the plants should be kept much cooler (18-20oC). If you don’t have good indoor growing conditions, you can try starting seeds late enough that you can safely put the seedlings outdoors in a cold frame during the day. You must bring them indoors every night, though, until temperatures stay reliably above 12oC at night.
What are the most common pests found in gardens on the West Coast and what are some tips for preventing them?
Pests we can count on in most gardens are carrot rust flies, which attack carrots, parsnips and related plants, and cabbage root maggots, which attack cabbage family, including radishes and turnips. These are both root flies, whose immature stages are tiny maggots that feed in roots. Both pests are easy to avoid by covering carrots and small cabbage family plants with insect netting to prevent adult flies from reaching the plants to lay their eggs. For larger plants, such as broccoli and cabbage, you can install a simple barrier around the stem of each plant at transplanting time. It should fit tight to the stem and lay flat on the soil surface to keep flies from laying eggs at the base of the stem.
Barriers for cabbage maggot
A challenging new pest in the region is the spotted wing Drosophila, which is a kind of fruit fly that attacks all berries and soft fruit. Early ripening varieties, such as June-bearing strawberries, usually miss being infested, but fruit that ripens in August and September can be badly attacked. As with the root maggots, the best approach for home gardeners right now (research is continuing) is covering bushes and trees with insect netting while the fruit is ripening.
Carrot Rust Fly Damage
Other pests, such as various aphids and caterpillars, are usually kept in check by beneficial insects, spiders and birds. The best approach for gardeners is to focus on making their garden safe and attractive for natural enemies: don’t use pesticides (even so called ‘safe’ products) and do plant flowers, such as sweet alyssum and others with tiny, nectar-rich flowers that feed beneficial insects.
What can I do to reduce the loss of seedlings to wireworms?
Reduce losses to wireworms in this year’s crop by picking them out of the soil when you see them and by attracting them to potato baits so that you can remove them. Starting a few weeks before you want to plant, bury chunks of potato an inch or two deep. Check them every few days and destroy any wireworms burrowing in to the bait. Wireworms take 3-6 years to complete their life cycle so it takes several years to clear them out of garden soil. Planting late can reduce damage, too, because wireworms burrow deeper in the soil as it warms. Do plant extra seeds to allow for some losses, especially with large seeds such as corn.
For long-term wireworm control, prevent the adults (called click beetles) from laying eggs in the garden beds. They lay eggs in the spring on grasses, but will also lay on legumes and weedy patches. Keep your beds weed free all winter, preferably under a thick leaf mulch, and don’t grow fall rye as a cover crop to turn under in the spring: that’s just a magnet for click beetles.
Wire worm bait potato
Winning Giveaway Question
Is it best to use heirloom seeds from the Pacific Northwest region, or are there advantages to also ordering and planting seeds adapted to other areas?
Using varieties adapted to the PNW is a good place to start because they are likely to grow well. But there are a lot of interesting, tasty and excellent varieties from other areas. For winter hardy vegetables and crops for coastal areas, varieties from Great Britain and the Netherlands are a good bet because they come from a similar climate and latitude (my favorite winter cabbage is the Dutch variety Langedijker Red—just don’t ask me to pronounce it!). A couple of things to watch for: Varieties of tomatoes and peppers developed in regions with long, warm growing seasons likely won’t produce much outdoors in cooler PNW summers, though they could be fine grown in a greenhouse. For onions, it is important to look for varieties suited to northern latitudes because they form bulbs in response to the long days and short nights of early summer. Many onions for southern regions (Texas and southern US) make bulbs under short days and may not produce bulbs at all when planted this far north (there are also day neutral onions, which can be grown widely).
As the changing climate delivers ever more variable weather, I think it is worth trying as many different varieties each season that we can, including those from other regions, to find ones that can handle the weird weather. During the long dry summer of 2015, I was surprised to discover how poorly a couple of long-time favorite onion varieties did. Other onion varieties produced a good crop in the same bed showing they were better adapted to the unusual conditions than my old favorites.
We have just moved to Vancouver Island and discovered our property is covered in clay but with some drainage (we’ve happily got our garlic strain coming up). Do you suggest raised beds or building up the soil by working our way down through it?
Clay soils make excellent vegetable garden soils because the fine particles hold lots of nutrients and water. But clay is sticky and easily compacted and when that happens air can’t get in (roots, earthworms and other soil organisms need to breathe) and water can’t drain. If clay soil is worked while it is wet you end of with rock hard clods. To avoid compacting your soil cultivate as little as possible and don’t walk on it.
Corn roots provide organic matter
Drainage is often a problem for clay and the heavy, dense soil warms up slowly in the spring. Both of these drawbacks are usually addressed by building raised beds, though if the site is on a warm slope that might not be necessary. You don’t have to build sides for raised beds or bring in additional soil: shovel topsoil soil from the pathways onto the beds to mound up the soil. While you are doing this, be generous mixing in compost. This is a good time to add lime if needed (get a soil test for pH) and a complete organic fertilizer so that you don’t have to disturb the soil again before planting your vegetables this year.
Don’t try to change the texture of your soil by adding sand: to make a difference you would have to replace something like half of the existing soil through the whole root zone. Instead, concentrate on improving soil structure by adding organic matter. Mix in compost, layer organic mulches (leaves, straw, crop waste) on the surface and leave behind as many plant roots as possible when clearing up crop residues. The combined activity of roots, soil microbes, earthworms and other organisms, plus humus (highly digested organic matter), clumps together the fine clay particles into larger crumbs leaving air spaces between them. With time, as the structure of your soil improves, it will look like a cross-section through chocolate cake--just what you want!
Linda Gilkeson is a passionate organic gardener with over 40 years of gardening experience. She is a regular instructor in the Master Gardener programs in BC and has led hundreds of workshops on pest management and organic gardening. Linda is deeply committed to preserving natural ecosystems through conservation and public education. She lives in the Gulf Islands of British Columbia, Canada.