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Oil-based insecticides have come a long way in the last few decades. Lighter and more versatile than the “dormant oils” of yesteryear, today’s horticultural oils can be used at most times of the year and are effective against a wide variety of insects. They’re also among the most benign pesticides, decomposing within a few days of application and causing minimal harm to beneficial insects and other untargeted organisms. Accordingly, many brands of horticultural oils are OMRI LISTED for organic gardening.
Most new-wave horticultural oils derive from petroleum, although an increasing number are vegetable-oil-based. In all cases, they’ve undergone several rounds of processing to remove impurities, such as sulfur that can damage leaves and other soft plant tissues. Their relatively high purity (92 percent or greater) and low viscosity allows them to go places – such as directly on foliage – that are largely off limits for old-school “dormant oil sprays.”
Almost all horticultural oils work not by poisoning pests but by mechanically coating and smothering them. Consequently, they’re an excellent remedy for infestations of slow-moving, soft-bodied arthropods, such as aphids, mites, and whiteflies. They also control a number of plant diseases, including powdery mildew and aphid-transmitted viruses.
Neem oil departs from the norm by disrupting insects’ feeding and development via several biologically active compounds. Virtually non-toxic to humans and other mammals, it’s effective against a relatively wide range of pests, including some that are resistant to other horticultural oils.
Horticultural oils come with a few provisos. First, they lose their effectiveness in rain, drought, cold (sub-40 degrees F), heat (90-degrees-plus), or high humidity. Additionally, even highly refined horticultural oils can sometimes cause minor damage to flowers and tender new plant growth. Horticultural oils are also said to be mildly toxic to a number of plant species including ferns, Japanese maples (Acer palmatum), and smoke trees (Cotinus spp.), although this may not apply to the highly purified oils currently in use.
Of course, horticultural oils are effective and ecologically friendly only when they’re properly used on visible pests at vulnerable points in their life cycles. A thorough, targeted coating of oil at the right time will put a serious dent in a susceptible pest infestation. Conversely, indiscriminate spraying will likely do more harm to beneficials and foliage than to pests. It’s always good horticultural practice to know your enemy and to read the label.
The horticultural oil season begins in late winter, as temperatures moderate and overwintering pests begin to shake their slumber. Hemlock woolly adelgids (pest info here), euonymus scale (pest info here), and spruce spider mites (pest info here) are among the insects and mites to look for and treat at this time.
Use horticultural oils from mid-spring to fall to control the likes of aphids, lacebugs (pest info here), spider mites (pest info here), powdery mildew (pest info here), and sawfly larvae such as “rose slugs” (pest info here). Mild days in late fall are a good time to spray scales, mites, and other pests that survived early spring treatment.
Indoor plant pests are also fair game, whatever the season. Your spider-mite-infested weeping fig and all your other insect-plagued houseplants will welcome a quick visit to the back porch for a spritz of death-dealing horticultural oil. Or you can give your plants (and their insect pests) a bath by inverting them into a bucket filled with highly diluted horticultural oil. Outside or in, horticultural oils are an environmentally friendly solution to a host of insect problems.
The first and perhaps most important choice in creating a garden is this: will it work WITH its surroundings, or against them? We can try to grow what we want to grow, heedless of the garden’s natural and domestic conditions, or we can choose plants and strategies that fit the situation on (and under and above) the ground. We can pour on the labor and chemicals to try to force the garden to bow to our will, or we can go with its currents, letting its characteristics be our guide. One choice leads to landscapes that are at odds with their setting, such as lawns in Phoenix. The other leads, in some cases, to permaculture.
Permaculture means different things to different people. Perhaps its ideal goal, though, is to create a landscape that sustains itself, its natural surroundings, and the people who steward it. Such a landscape rides with the rhythms of nature, with plants and microbes and soil and air working together as a cohesive, self-nurturing unit that requires minimal inputs of nutrients and labor. Here are some ways to do this.
Know your site. What are your soil and sun factors? What plants best fit your yard and wants? Then you can make smart choices for your yard and garden. (Much as you love raspberries, they’ll languish in too much shade. How about elderberries instead?) The garden’s domestic setting is also a factor. For instance, plantings should generally become less formal and more naturalistic with distance from buildings and paths.
Work with natural cycles and processes. Start a compost pile for spent vegetation and uneaten produce, to return their nutrients and organic matter to the soil. Mulch with beneficial amendments (such as Fafard Garden Manure Blend) and fertilize with organic materials that support beneficial soil microbes and boost organic matter. Disturb the soil as little as possible, to maintain its structure and to avoid bringing buried weed seeds to the surface to germinate.
Sustain “good” insects by minimizing pesticide use and by utilizing plants that attract them (such as members of the parsley and aster families). Cut back native perennials in early spring rather than fall, to provide food for birds, protection from erosion, and refuge for beneficial insects.
Use a wide diversity of plants – including natives – that complement and balance each other horticulturally and ornamentally. Try for a harmonious patchwork of species with different forms, colors, pollinators, pests, associated beneficial insects, and other characteristics. Include a variety of trees, shrubs, and perennials to provide structure, and interplant with numerous edibles and ornamental annuals to increase diversity and yield. Intermingle heavy-feeding plants (such as tomatoes) with nitrogen-accumulating plants (such as legumes) to balance and replenish soil fertility. Introduce some non-invasive, self-sowing ornamentals and edibles (such as celandine poppies and perilla and forget-me-nots), which make excellent subjects for a dynamic, self-sustaining landscape.
Create plantings that have multiple uses and functions. Why not plant a couple pawpaw trees, whose handsome, rounded, bold-leaved crowns will produce fruit for the table and provide food for zebra swallowtail caterpillars? Or a highbush cranberry, for its platters of white, late-spring flowers; its fall harvest of red berries that make excellent preserves; and its attractive maple-like foliage that turns burgundy tones in fall? Or the stately American persimmon tree (Diospyros virginiana) with its edible fall fruits prized for baking? Or one of the many colorful leaf vegetables (such as ‘Rainbow’ chard and red orach) that are both ornamental and tasty?
Connect the garden to surrounding natural areas by using plants that attract, shelter, and feed native insects and animals. A clump of columbine will draw local hummers to their nectar-rich flowers; a planting of winterberries (female and male) will feed yellow-rumped warblers and cedar waxwings and mockingbirds with their brilliant red berries; and a Dutchman’s pipe vine will host pipevine swallowtail larvae, which make excellent food for nestlings. Then there’s the ever-popular milkweeds, which are essential to monarch butterflies.
Consider integrating “volunteer” seedlings of native plants into the garden, rather than indiscriminately weeding them out. Conversely, avoid introducing plant species (such as winged euonymus and Japanese barberry) that are likely to invade and disrupt nearby natural areas.
At its best and most satisfying, a garden that follows these principles develops into a dynamic little ecosystem of its own, where plants and wildlife and humans all have a place. Permaculture does not aspire to “permanent” landscape features such as a perpetually green, weed-free lawn. Rather, it’s a collaborative effort between plants and gardener to create a cultivated landscape that is shaped and steered by nature’s ever-changing forces. A permaculture garden never stops evolving – just as a permaculture gardener never stops learning and marveling.
For the past 11 years, I have grown my vegetables in a community garden plot, which has provided a rough, real education in plant pests, diseases, and weeds. Why? Because these mega veggie gardens are pest hot spots, and summer is the worst time of year for the beasties. “Bad” insects always attack my beans, cucumbers, tomatoes, and eggplants–threatening to destroy fruits and foliage, and sometimes spreading disease as they munch and crunch along. I must use every tool in the toolbox to fight them. And, if the bugs beat my crop, I often start the crop again, if there is time and the season allows. Sometimes beating pests is just a matter of retooling planting time.
The five most common vegetable garden pests that I battle in mid to late summer are Colorado potato beetles, striped cucumber beetles, eggplant flea beetles, Mexican bean beetles, and harlequin cabbage bugs. Each return year after year with regularity, but some years are worse than others. The severity of the previous winter usually indicates the severity of my pest problems–the milder the winter, the harsher the pest problem. Last winter was pretty mild, so this summer the pests are rampant. Here are some ways that I have learned to overcome them.
The surest way to attract Colorado potato beetles to your garden is to plant potatoes, but if you don’t have potatoes, they will go for your tomatoes and eggplant secondarily. (Fortunately, they don’t appear to be attracted to tomatillos.) The fat, striped adult beetles emerge from the soil in late spring to feed on emerging potatoes and then lay clusters of orange-yellow eggs on leaf undersides. The eggs yield highly destructive little orange larvae that eat foliage nonstop and grow very quickly. You can kill the insects at any stage, but it’s easiest to pick off the adults and eggs. (Click here to view the full life cycle of these beetles.) The beetles can complete up to three life cycles in a single season, so once you have them, you generally have to fight them all summer.
These insects are highly resistant to insecticides, so it pays to choose non-chemical methods of control. Time and time again, well-timed cultural control, and good winter cleanup have proven to be the best means of battling them. Cultural control is essentially “picking”off the adults, eggs, and larvae and/or pruning off egg- and larval-covered leaves and branches. I generally smash picked specimens, but you can also drown them in a bucket of water. Good picking should start in mid to late spring and continue until all signs of these pests are gone.
(To learn everything there is to know about Colorado Potato Beetles, visit potatobeetle.org.)
As their name suggests, striped cucumber beetles favor cucumbers, but they also attack melon vines. Small, striped cucumber beetles look so cute and innocent, but they are so destructive. Every year my cucumber crop is a crap (or “crop) shoot. Why? It’s not because of the damage they cause by feeding on the plants and fruits but the catastrophic bacterial wilt that they spread from plant to plant. Once cucumber vines get cucumber bacterial wilt, there is no turning back. The leaves will start to show droop and eventually whole stems will collapse and the vine will die.
These pests may have two to three cycles in a season and are next to impossible to control, even with harsh chemical insecticides. Floating row cloth cover can keep them at bay, but it is a hassle and does not allow pollinators to reach the plants. For me, the best course of action is to choose bacterial-wilt-resistant cucumber varieties. Cornell University Extension offers a great list of resistant cucumber varieties to choose from. Of these, I have grown the short-vined slicer ‘Salad Bush‘, which is great for container growing. Two more reliable varieties are ‘Marketmore 80‘ and ‘Dasher II‘.
Tiny jet-black eggplant flea beetles are the smallest summer pests in this list, but they can devastate an eggplant in a matter of days. The small but numerous insects leave little pock marks all over a host plant’s leaves. Badly damaged leaves barely photosynthesize, resulting in poor, weak plants that produce puny fruits.
If you want to grow eggplant, you have to protect them from eggplant flea beetles. There are plenty of insecticides that will kill these insects, but only a few non-chemical cultural practices will stop them. The best method that I have found is protecting plants with summer weight floating row covers that transmit a lot of sunlight while physically keeping insects from the plants. The key is covering plants early and then securing the row covers at the base, so the tiny beetles cannot crawl beneath them. Holding cover edges down with bricks, pins, and even mulch or compost, works. The only caveat is that you may need to hand-pollinate plants for fruit set.
Good fall cleanup of infested crop plants will also keep populations down from year to year. On average, eggplant flea beetles will complete up to four generations in a single season.
These ornamental stink bugs are the worst enemy of summer kale, broccoli, and other brassicas. They suck the juices from the leaves causing pock marks all over them. The most striking destruction I have ever witnessed was with an enormous Portuguese kale that I had nurtured to a bold 2′ height through spring. Once the numerous beetles started to attack in early summer, the plant had no chance.
There are a few management practices that will help stop these bugs. Floating row covers can also be used, as was suggested for the eggplant flea beetles, but harlequin cabbage bugs are big enough to pick off by hand, if you have the time and can handle the slightly stinky smell they emit when disturbed. Small nymphs are also susceptible to treatment with OMRI Listed® insecticidal soap.
Two to three generations of harlequin cabbage bugs can occur each season. By late summer, they are no longer a problem, so you can plant your fall cabbages and kales with confidence.
Like Colorado potato beetles, it’s the larvae of Mexican bean beetles that do the harshest damage to bean plants. The adults emerge in late spring but they rarely cause major problems on bean plants until midsummer. The adults are orange, black-spotted beetles that lay clusters of orange-yellow eggs below the leaves, much like the Colorado potato beetle. The unusual larvae are fuzzy, bright yellow, and devastate leaves as they feed along the leaf bottoms.
You can control these pests as you would Colorado potato beetles with one exception – destructive harvesting. Destructive harvesting is the harvest and total removal of infested plants from the garden. After picking, infested plants should be pulled, bagged, and taken far from your garden. (Click here to view a YouTube video from the University of Maryland about destructive harvesting.) Beans can be replanted as late as mid August for early fall harvest.
In general, regular weeding, good plant care, and excellent garden clean up, in summer and fall, will help keep pest populations down. Clean the ground of all leaf litter and weeds, and amend the soil with top-quality amendments for vegetables, such as Fafard® Garden Manure Blend or Natural & Organic Compost, and your plants will be more robust to resist the many garden pests that threaten to destroy them.
Rain and snow melt make spring garden soil preparation a challenge every year, but once you can get into the garden, get into your soil! Feeding your garden soil in spring is an investment that pays off every time. Amending, turning, tilling, fertilizing, and mulching are the five practices needed to make your garden great all season! The addition of drip hoses for easy irrigation can make garden care even more effortless.
Rich soil yields better crops, so it pays to feed your soil. Adding the best amendments will ensure your soil is ready to work. Adding lots of compost will increase good yields, but be sure that your compost is good quality. Fafard Premium Natural & Organic Compost is a high-performing compost sure to give your garden what it needs. For areas where you intend to plant greens, go with nitrogen-rich amendments, such as Fafard Garden Manure Blend.
“No till” areas in the vegetable garden need different care. These include beds with perennial and winter crops, like areas with asparagus, garlic, strawberries, or hardy herbs, as well as well-amended spots that are already in good shape below ground. Still, adding extra organic matter to no-till spots will ensure better growth while allowing for the addition of needed amendments. Adding a layer of compost and lightly turning it into the surface will increase organic matter while not disrupting your plants or soil structure.
Many gardeners have bed areas that are tilled yearly. This has its pluses and minuses. Tilling brings the bank of weed seeds to the surface and disrupts soil structure and organisms, but it also increases tilth and allows organic matter to be worked deeply in the soil. If you plan to till, plan to double your amendment by adding a till-in layer and a mulch layer. First, put down a thick layer of compost or manure and till it deeply into the soil, then rake and berm bed spaces as needed. Finally add a second layer of compost to further enrich the soil and protect against weeds. The second step is extra important because tilling brings lots of weed seeds to the soil’s surface.
Many vegetables require lots of food to produce good yields through the season. It’s essential to feed the garden well from the beginning with a good tomato & vegetable fertilizer. OMRI Listed fertilizers approved for organic gardening are best. Simply broadcast the fertilizer and gently work it into the top layers of soil where it’s needed most. Heavy feeders, such as tomatoes, peppers, and melons, should be fed again at planting time.
In addition to adding a compost mulch layer, I protect and define walkways with leaf mulch, straw or hay, and grass clippings. These natural mulches stop weeds and make it easier to traverse the garden in wet, muddy weather. They also hold water and keep root zones cool on hot summer days. By fall’s end, they have usually broken down into accessible organic matter.
Living mulches are another option. Planting a dense summer cover crop in walkways, like white clover, will keep them tidy, cool, and mud-free while also feeding the soil. Just be sure to keep the edges trimmed and turn plants under in fall.
When adding amendments, determine how many inches you want to add over your garden area. Here is the simple formula needed to determine this:
For added benefit, consider snaking a drip hose beneath mulch layers to make summer watering easier and more efficient. Below-the-surface watering keeps water at root zones while virtually stopping surface evaporation on hot days. The key is marking your drip lines from above (to keep from accidentally cutting the line with gardening tools) and securing nozzles for easy access. At watering time, just hook up your lines and let them drip for an hour or so to ensure deep watering.
Once the vegetable season takes off, your garden will be in good shape with these five steps. Sure, weeds, drought, and hot days will come, but their impacts will be minimized and your time and garden’s productivity will be maximized.
One of the highlights of the gardening season comes in the depths of winter, with the arrival of new catalogs brimming with enticing new varieties. The following are among the best of the new vegetables for 2015.
A hybrid of two long-time favorites, ‘Jersey Boy’ produces bright red, half-pound tomatoes that “brilliantly join ‘Brandywine’s sublime sweet-sour tang with ‘Rutgers’ classic rich color, shapeliness, yield and performance.” It debuts in the 2015 Burpee catalog, as does ‘Cloudy Day’, which reputedly bears good crops of 4-ounce fruits even in areas too cool for most tomatoes. 2014 All-America Selection Winner ‘Chef‘s Choice Orange’ wins plaudits for its “deep orange, beefsteak shaped fruits” with “firm, sweet, mild flesh.” They ripen relatively early on tall, 5-foot vines. Smaller in all its parts is another 2014 AAS winner, ‘Fantastico’, which yields 10 or more pounds of rich red, grape-sized tomatoes on compact plants suitable for large containers. For lovers of old-time tomatoes, Johnny’s Selected Seed now offers the Heirloom Collection, a seed mix comprising ‘Brandywine’, ‘Striped German’, ‘Cherokee Purple’, ‘Amish Paste’, and other classics.
New introductions for 2015 also include many veggies from outside the tomato aisle. Among the most notable are two pea varieties from the hand of Dr. Calvin Lamborn, father of the snap pea. The fleshy, 3-inch, deep purple pods of ‘Royal Snow’ make a tasty and ornamental addition to salads and other dishes (and the pink flowers are pretty too). They are also good lightly cooked. Vines of ‘Petite Snap-Greens’ are harvested when young for tossing into salads or using in stir-fries. Both varieties are available from Johnny’s.
The bush bean ‘Mascotte’ holds its long, slender, tasty pods on stems that rise above the plants’ low, mounded leafage. With its compact habit and long harvest season, it’s perfect for containers (in a fertile, humus-rich growing mix such as Fafard Professional Potting Mix) or narrow garden beds. Its many virtues earned it an AAS award, the first for a bean variety since 1991.
AAS winner ‘Cinderella’s Carriage’ derives its name from the flattened, carriage-ready shape of its large, reddish-orange pumpkins, arrayed on vigorous, powdery-mildew-resistant vines. As many as seven mini-carriages are produced per plant. Similar in shape (but much smaller in size) are the fruits of a new summer squash variety from Burpee, ‘Cupcake’. Their tasty, savory-and-sweet flesh and tender dark green skin suits them for many uses including roasting, grilling, and slicing into stir-fries.
A panoply of peppers debut this year. Two AAS winners head the list: zingy-fleshed ‘Giant Ristra’, whose fire-red, 7-inch-long fruits are perfect for stringing into swags or wreaths; and gold-fruited, sweet-flavored ‘Mama Mia Giallo’, which also offers the virtue of a compact plant habit. Its long, conical, often curved peppers are delicious fresh or roasted. Burpee introduces an 8-inch, pale-green Italian frying pepper (‘Long Tall Sally’); an early-fruiting banana type (‘Blazing Banana’); a large, moderately hot, Ancho-Poblano variety with dark glossy skin (‘Big Boss Man’), and a jumbo, foot-long, sweet red Marconi-style selection (‘Thunderbolt’).
And of course there are cucumbers. Compact-growing, early-bearing ‘Pick a Bushel’ is a great fit for cooler regions (as well as container gardens), producing basketfuls of cukes early in the season. Firm, flavorful, and sweet, they can be harvested young for pickles or allowed to mature to slicing size. Matures in 55 days from sowing. Fellow AAS winner ‘Saladmore Bush’ offers many of the same virtues, but bears over a longer season on somewhat longer vines.