Two new studies implicate systemics in bee problems
"Field Research on Bees Raises Concern About Low-Dose Pesticides
Erik Stokstad
Five years ago, bees made headlines when a mysterious condition called colony collapse disorder decimated honey bee colonies in parts of the United States. Now bees are poised to be in the news again, this time because of evidence that systemic insecticides, a common way to protect crops, indirectly harm these important pollinators. Two field studies reported online this week in Science document problems. In bumble bees, exposure to one such chemical leads to a dramatic loss of queens and could help explain the insects' decline. In honey bees, another insecticide interferes with the foragers' ability to find their way back to the hive. Researchers say these findings are cause for concern and will increase pressure to improve pesticide testing and regulation."
Don't apply systemic insecticides such as imidacloprid (Merit) to plants that are visited by bees.
Monday, April 2, 2012
Monday, March 26, 2012
Tomato season: just around the corner!
Tomato season is nearly upon us, and every year we get a new crop of gardeners wanting to grow America’s favorite vegetable.
Good news: we live in tomato country. The plants are very easy to grow here, we have a long growing season, and if you select the right variety you will get plenty of fruit. But a lot of folks are really jumping the gun, wanting to plant before the soil is warm. On Saturday a gentleman asked me, “isn’t it time to plant tomatoes?” He was wearing three layers of clothing and a wool hat. The temperature Saturday topped out at 50 degrees. The low was 37. We had a light frost a little over a week ago (March 19). The soil temperature, according to the Davis weather station, is at 53 degrees.
So my answer to him was No. Are you wearing shorts in the garden yet? That’s a good indicator. Put on your shorts (if you’re modest), go out and sit on the garden bed. Uncomfortable? The plants will be too.
Tomatoes prefer a soil temperature of 70 degrees! We usually achieve that when nights are 50 – 55 degrees and daytime temperatures are in the 70’s for several days in a row. By the calendar, that is usually late April at the earliest. You can plant anytime through June with good results here.
What happens if you plant too early?
The plants sulk and don’t grow. Leaves turn purplish, due to nutrient deficiencies caused by cold soil. If there is rain, and if the plants had any fungus infection, it spreads rapidly from leaf to leaf. Snails, slugs, and earwigs eat leaves. In short, you are planting your tender greenhouse-grown seedling into a hostile environment. Ultimately it may recover and grow when temperatures warm up. But a later-planted seedling that goes into warm soil will give better results.
Nevertheless, there are benches full of tomato seedlings at every garden shop now. So if you do buy some baby plants, keep them up close to the house where the building can provide some warmth. Check those nighttime temperatures. Amend your soil now with compost.
Select the right variety? Don’t they all do well here?
Nearly all tomatoes grow vigorously in the Sacramento Valley. Getting leafy tops is not a problem. But not all produce fruit reliably. A few varieties are more heat sensitive, meaning that the blossoms fall off without producing fruit when daytime temperatures are above about 85 degrees. For that reason, we do not recommend any of the Beefsteak varieties (Beefsteak, Beefmaster, Supersteak) or the heirloom Brandywine tomatoes. The plants grow to 8 to 10 feet, and produce 3 to 4 fruit total. Very disappointing.
What should I look for when buying plants?
Deep green color. It’s not a problem to buy tall, even overgrown tomato plants. Avoid plants with spots on the leaves, as they may be infected with early blight fungus. I pick off flowers, if any, when I plant because I want the plant’s energy to go into growth, not fruit production, in its first weeks. A note about spots: I have seen some plants with bleached-looking blotches on the leaves. Those came out of the greenhouse and got stressed by cold weather. They will recover.
Which ones do grow and produce well?
There are over a hundred varieties of tomatoes available to choose from at local stores. As a generalization, hybrids yield more heavily, and heirloom tomatoes have more interesting fruit. So a mix of hybrids and heirlooms gives the best results. Try some tried and true varieties, and experiment.
What is an heirloom? A hybrid? Are any of them GMO’s?
Heirloom varieties are older varieties that have been handed down for generations. They are open-pollinated, meaning that (with care to avoid cross-pollination) you could save the seed. Most heirlooms have some special character. That could include interesting color, less-acid flavor, meatier or juicier fruit. Often they are regional: the Brandywine heirloom varieties come from Brandywine region of Pennsylvania, where they are well adapted.
Cross-pollinating certain parent plants, to get seedlings with the desirable characteristics of the parents, creates hybrid tomatoes. Disease resistance, higher yield, extra flavor and color, more compact habit. Seedlings grown from fruit of hybrids will not come true.
No tomato varieties that you buy are genetically modified in the sense of having genes inserted into them. Hybrid or not, they aren’t GMO’s.
Do the heirlooms taste better?
Many have special flavor. But hybrid tomatoes often win blind taste trials as well. Early Girl, a popular hybrid variety that is especially well adapted here, scores very high. Flavor is most affected by how you water. Deep, infrequent watering concentrates the flavor of any variety.
Do they need special food?
Don’t over-fertilize tomato plants! We have rich soil here. Too much nitrogen leads to too much top growth and poorer fruit production. My preference is to turn in a planting compost that contains some organic source of fertilizer at the time of planting. That’s all I use. If you use a fertilizer, lower-nitrogen types are best. The first number on the bag should be less than 10, such as 4-5-3 or 5-5-5.
How much sun do they need?
Tomatoes yield best in full sun. Half-day sun can work, but at least four to six hours is preferred. If you have more shade than sun, consider a cherry or sauce tomato. Or look for the new hybrid called Shady Lady, which produces a surprisingly large crop of large, flavorful fruit in less sun than most others need.
Should I plant them deeper in the ground?
Yes. We don’t do this with other plants, but tomatoes benefit from deep planting. They will send out roots from the nodes (where the leaves are) and get a better root system.
You said they get eight feet tall?! Don’t they run all over the ground?
The tomato plant is a vine. A few shorter varieties exist. Those are called “determinate,” and they only grow to 4 feet or so. All others get 6 to 8 feet or bigger, and they will run all over the place if you don’t stake or cage them. Techniques vary. For example, a single stake on each plant, to which you continue tying the plant until mid-summer. Better is a metal cage made from concrete wire, anchored securely, which the plant fills up. You reach in to pick the fruit.
Some favorite hybrid varieties.
o I always plant Early Girl hybrid for reliable yield and excellent flavor.
o For production for processing, I do one of the reliable vigorous hybrids such as Champion or Better Boy. Mortgage Lifter and Stupice (pronounced Stew-peach) are high-yielding heirlooms.
o For sauce and salsa, I wouldn’t be without Juliet hybrid.
o For people to nibble in the garden, the most popular cherry tomato ever is the orange-fruited, tangy-flavored SunGold hybrid.
Some of my favorite heirlooms include:
o Abraham Lincoln is becoming a favorite, with deep red fruit, high yields, and rich flavor.
o Costoluto Genovese, an Italian variety with large, meaty, fluted fruit. This one yields exceptionally well for me and has become one of our favorites.
o Pineapple. Very large yellow fruit are striped with red, very sweet; the plant is very productive. Lemon Boy is a yellow hybrid with high yields and good flavor.
o Plant a striped or purple variety, just for interest. Mr. Stripey, Green Zebra, Cherokee Purple, are good examples.
o Caspian Pink and Giant Belgian are very large-fruited heirlooms (fruit often over 1 lb each) that have given good yields some years. They are very sweet.
o Red Currant and Yellow Pear are small-fruited heirlooms popular with kids. Very high-yielding!
o Try something you’ve never heard of! You may find a new family favorite.
What about peppers and eggplants?
Don’t plant them in cold soil. Plants that go in too early never yield as well as those that are put into warm soil later in the season. May is best.
Tomatoes are subtropical plants! When it feels subtropical, go ahead and plant your garden. Meanwhile, keep the seedlings warm, get your garden ready, and start collecting recipes.
Charts of tomato (and pepper) varieties can be found on our website at redwoodbarn.com
Click on link for pictures:
Abraham Lincoln
Abraham Lincoln is a good all-purpose red heirloom tomato. Good yield, excellent flavor.
Costoluto Genovese
Costoluto Genovese: our family’s favorite heirloom! Big fluted fruit, beautiful color, rich flavor, and very meaty. This heirloom gives me good yields consistently.
Juliet
Juliet hybrid is prolific! The plants produces well over a hundred small, pear-shaped meaty fruit. Freeze them whole, use in salads, salsas, and sauces. Or just eat right off the vine.
Lemon Boy
Lemon Boy is a yellow hybrid tomato. Medium-size fruit is abundant. The skin is a little tougher than other yellow types, so it hold up better in bad weather.
Pineapple
Pineapple is a beautiful heirloom tomato, yellow with a red blush and often with red streaks in the skin and flesh. It has a sweet, very large fruit, and reasonable yield. The thin skin is somewhat vulnerable to weather damage.
Shady Lady
Shady Lady is a new hybrid tomato that produces well with less sunlight than other varieties. Determinate type, meaning the plant gets to only 3 to 4 feet tall. Excellent flavor and yield.
Sungold
Sungold hybrid cherry tomato has become a garden favorite. It produces hundreds of golden fruit, with rich, tangy, sweet flavor.
Wednesday, March 14, 2012
Sunday, March 4, 2012
Mandarins? You Can Grow That!
Gardeners in Northern California can grow a lot of different kinds of fruit. Here in the Sacramento Valley we get enough winter chilling to grow nearly all the deciduous fruit species, yet are mild enough most winters to grow the majority of citrus varieties as well.
Among the citrus, mandarins are very popular. They peel easily, they are very sweet and tangy, many are seedless, and each variety ripens over several weeks in the winter or spring.
One other advantage? They’re the most cold-hardy of the common citrus varieties. And with some of the new varieties that have been introduced you can stretch the harvest season from fall through spring.
When I was growing up the best-known mandarin was Dancy. It is the one typically called a “tangerine,” and ripens around the holidays. It does have seeds, which we would spit at each other out on the pation while we waited for the grownups to get out of bed on Christmas morning. Very rich flavor.
In recent years Satsuma mandarins have become the most popular types, with Owari Satsuma the most common cultivar. For years it has been described as the hardiest of all mandarins (perhaps now superceded by Yosemite Gold). Ripens November - January. Seedless, peels easily, easy in containers, and one of the smallest trees (more like a bush, really). Several clones are grown; most common is ‘Frost Owari’. ‘Dobashi Beni’ has darker color.
An increasingly important commercial mandarin is Clementine. This variety from North Africa ripens about a month after Satsuma and has very good flavor. “Cuties” are a marketing ploy using small, early Clementines (and Murcotts). They are seedless if they are isolated from other citrus. Note: Pixie is a small mandarin that has been around for years, and the marketing of Cuties is causing some confusion. Pixie has small fruit with a mild, pleasant flavor. Introduced in 1927, it came into the trade in the 1960’s.
A few other important varieties:
Gold Nugget is popular with citrus connoisseurs. Seedless, mid to late season, it has very rich, sweet flavor; “...considered by professional taste panels to be one of the very best flavored citrus in the world.”[UCR]
Three new introductions from UC Riverside, introduced in 2002, have increased the hardiness and ripening range of mandarins.
Shasta Gold: Large fruit is mid-season but holds well on the tree. This triploid is naturally seedless, even when cross-pollinated. Good color, very juicy, very sweet.
Tahoe Gold: Fruit is early but does not hold well on tree. Very juicy, sweet, and productive.
Yosemite Gold: Late ripening, holds well on the tree. Naturally seedless, even when cross-pollinated. Good color, very juicy, very sweet.
There are many species of citrus, and a lot of natural and intentional hybrids. Mandarins are Citrus reticulata. Some hybrids with other species have also been created: the Indiro mandarinquat is a hybrid between kumquat and mandarin! The Rangpur lime is thought to actually be a sour mandarin, not a lime. And there are hybrids between Tangelo and mandarin (Page), Pummelo and mandarin (Cocktail), and more.
Citrus like a warm, sunny location. The soil should drain reasonably well, so in heavy-soil areas you should plant on a slight mound. Make a watering basin so you can water deeply, thoroughly, and infrequently. Young citrus like to be fertilized regularly: monthly or seasonally, depending on what you’re using. Yellowing leaves may indicate a lack of certain micronutrients. An established citrus tree is reasonably drought tolerant and requires no special pruning.
Citrus from your garden from fall through spring!
You Can Grow That! is a grass-roots project of independent garden centers, garden bloggers and writers, and other plant professionals!
Saturday, January 7, 2012
Thursday, December 29, 2011
After The Frost: What To Do?
plus: Planting for Winter Color
We have had a lot of frost this year! According to the weather records from the station west of UC Davis, there have been 18 mornings cold enough for frost since Nov. 1. This is a pretty typical La Niña pattern. Low rainfall = low dew points, less fog, and more frost on a clear, still night.
Lowest readings have been the mornings of Dec. 24 and 25 when that weather station recorded 24 degrees. Ordinarily temperatures that low could be expected to do pretty serious harm to citrus and other subtropicals. But damage so far has been minimal.
Microclimates are making a big difference. The areas up against your house on an east-facing or south-facing walls are several degrees warmer due to heat stored during the day, and are warming up quickly when the sun comes out. Cold damage on a plant is a combination of absolute temperature and duration. These frosts have been cold, but short duration.
Dry soil can lead to further damage from cold as plants desiccate. We are way behind on rainfall, with less than half of normal to date. Water newly planted plants, those in containers, and larger citrus and subtropicals. You can simply run your sprinklers through one cycle, or give each plant a quick soaking with a hose.
If your plant is showing damage, it's best to just leave it alone for now. Cutting back frosted leaves and stems opens the plant up to further damage. Those wilted, curled leaves, in some cases, actually provide a small measure of frost protection for parts of the plant further down. I prefer to wait until spring and let the plant begin to grow before pruning. Let the plant tell you how far to cut it back; just cut to the new growth when it occurs.
You've probably already figured out that your summer annuals won't be coming back. Impatiens, coleus, marigolds, and their ilk are dead. Don't rush to rip out begonias, as they often do resprout in spring from the base. Winter annuals are impervious to the cold. Pansies and violas, snapdragons, stock, ornamental cabbage and kale, and paludosum daisy may bend over with frost, but will perk right back up when the sun is upon them. Winter-flowering perennials such as cyclamen are also unaffected. Likewise in your vegetable garden: the salad greens, broccoli, cabbages, onions, and others are all perfectly hardy.
[Science quiz! Why do some plants survive cold and other not? Different chemicals in the leaves and stems. Plants that evolved in colder regions make natural anti-freeze.]
Should I keep the plants covered?
Only if the material you used allows light to penetrate. Covering a plant with a sheet or blanket has two drawbacks. Each point of contact with the leaves and stems is likely to result in damage as the cold transfers through the cloth. And the exclusion of light for more than a day or so will cause the plant to start dropping leaves.
Should I sprinkle the foliage to protect it?
This common agricultural practice is not practical for homeowners. You need continuously freezing layers of ice forming on the foliage through the freezing period (early morning before dawn). Sprinkling the leaves once doesn't make any difference.
Should I pick all the citrus fruit?
Only if you want a bunch of under-ripe fruit. Citrus don't ripen any further once picked, and most varieties aren't ready yet. Your Satsuma mandarins are ripe, but that also happens to be one of the hardiest citrus varieties. Lemons, navel oranges, and others are still tart. I'd be surprised if a couple of cold mornings have damaged the crop. Stripping the tree was appropriate in 1990 and 1998, when we had epic freeze events. A hard frost of a couple day's duration? I prefer to leave them on the tree.
Do I need to protect my rose bushes?
No. Roses are hardy here.
Cyclamen
We are fortunate to live in a gardening climate where we can have color year-around. The afore-mentioned winter annuals can be planted even in the coldest weather, and will continue to bloom into spring or even early summer. Pansies and violas are most popular due to the color range and profusion of bloom over a long period.
There are a few perennials that bloom mid-winter. Examples include bergenia, gazania, hellebores, and red-hot-poker (Kniphofia hybrids). Take a quick walk through the Ruth Storer garden at the west end of the UC Davis Arboretum to get some ideas; it is an all-season resource. On a recent visit the Kniphofia variety called Christmas Cheer was in full bloom.
Certain shrubs give us reliable winter flowers. Examples include the golden bush daisy (Euryops), laurustinus (Viburnum tinus), Oregon grape (Mahonia), rosemary, and the extra-fragrant sweet Victorian box (Sarcococca ruscifolia). Some winter-bloomers with special requirements include camellias and winter daphne. Well worth the effort, but ask before you buy.
We also enjoy the colorful foliage of a number of evergreen shrubs. Cold weather leads to interesting chemical changes within the leaves of certain plants, leading to bright pigments that are less obvious or missing in warm weather. Just part of the background shrubbery much of the year, these stand out in cold months. Examples include the common heavenly bamboo (Nandina domestica) and the purple hopseed bush (Dodonea viscosa purpurea).
One deciduous shrub with late-season color is Japanese barberry (Berberis thunbergii), whose leaves turn bright red in fall and then hang through December. It grows to five feet tall or so. A dwarf cultivar called Crimson Pygmy only grows to 2 to 3 feet tall and wide.
Colorful winter fruit is a bonus of citrus, and the hardiest one is also the most ornamental: the kumquat. Not everyone likes to eat the tart/sweet fruit. The peel is sweet and edible, the flesh is tart. So to eat a kumquat, you pop it in your mouth whole and chew it up. But even if you don't favor the flavor, you can appreciate the abundant bright golden fruit out in the yard. Kumquats are cold-hardy well into the teens, have fragrant flowers in the summer, and the plant has dense foliage and grows upright.
Many ornamental shrubs have colorful winter fruit, including natives such as Toyon (Heteromeles arbutifolia) and Coffeeberry (Rhamnus californica). There are great examples in the Arboretum near the road which goes to Mrak Hall. The non-native heavenly bamboo, mentioned above, also bears red winter fruit with the colorful leaves.
Is it ok to plant these selections now? Sure, if your soil is workable. Digging in muddy soil is bad for the soil structure. But one silver lining to our dry season is that soil can still be turned and proper planting holes can be dug. If not, just hold the plants in the pot until spring. Don't forget to water them if we don't get rain!
For statewide weather data, go to the UC Davis IPM web site and look for the "Weather, models, and degree days" link here. I use the Davis.A station.
We have had a lot of frost this year! According to the weather records from the station west of UC Davis, there have been 18 mornings cold enough for frost since Nov. 1. This is a pretty typical La Niña pattern. Low rainfall = low dew points, less fog, and more frost on a clear, still night.
Lowest readings have been the mornings of Dec. 24 and 25 when that weather station recorded 24 degrees. Ordinarily temperatures that low could be expected to do pretty serious harm to citrus and other subtropicals. But damage so far has been minimal.
Microclimates are making a big difference. The areas up against your house on an east-facing or south-facing walls are several degrees warmer due to heat stored during the day, and are warming up quickly when the sun comes out. Cold damage on a plant is a combination of absolute temperature and duration. These frosts have been cold, but short duration.
Dry soil can lead to further damage from cold as plants desiccate. We are way behind on rainfall, with less than half of normal to date. Water newly planted plants, those in containers, and larger citrus and subtropicals. You can simply run your sprinklers through one cycle, or give each plant a quick soaking with a hose.
If your plant is showing damage, it's best to just leave it alone for now. Cutting back frosted leaves and stems opens the plant up to further damage. Those wilted, curled leaves, in some cases, actually provide a small measure of frost protection for parts of the plant further down. I prefer to wait until spring and let the plant begin to grow before pruning. Let the plant tell you how far to cut it back; just cut to the new growth when it occurs.
You've probably already figured out that your summer annuals won't be coming back. Impatiens, coleus, marigolds, and their ilk are dead. Don't rush to rip out begonias, as they often do resprout in spring from the base. Winter annuals are impervious to the cold. Pansies and violas, snapdragons, stock, ornamental cabbage and kale, and paludosum daisy may bend over with frost, but will perk right back up when the sun is upon them. Winter-flowering perennials such as cyclamen are also unaffected. Likewise in your vegetable garden: the salad greens, broccoli, cabbages, onions, and others are all perfectly hardy.
[Science quiz! Why do some plants survive cold and other not? Different chemicals in the leaves and stems. Plants that evolved in colder regions make natural anti-freeze.]
Some common questions:
Should I keep the plants covered?
Only if the material you used allows light to penetrate. Covering a plant with a sheet or blanket has two drawbacks. Each point of contact with the leaves and stems is likely to result in damage as the cold transfers through the cloth. And the exclusion of light for more than a day or so will cause the plant to start dropping leaves.
Should I sprinkle the foliage to protect it?
This common agricultural practice is not practical for homeowners. You need continuously freezing layers of ice forming on the foliage through the freezing period (early morning before dawn). Sprinkling the leaves once doesn't make any difference.
Should I pick all the citrus fruit?
Only if you want a bunch of under-ripe fruit. Citrus don't ripen any further once picked, and most varieties aren't ready yet. Your Satsuma mandarins are ripe, but that also happens to be one of the hardiest citrus varieties. Lemons, navel oranges, and others are still tart. I'd be surprised if a couple of cold mornings have damaged the crop. Stripping the tree was appropriate in 1990 and 1998, when we had epic freeze events. A hard frost of a couple day's duration? I prefer to leave them on the tree.
Do I need to protect my rose bushes?
No. Roses are hardy here.
On a more cheerful note, how about some color in the garden in mid-winter?
Cyclamen
We are fortunate to live in a gardening climate where we can have color year-around. The afore-mentioned winter annuals can be planted even in the coldest weather, and will continue to bloom into spring or even early summer. Pansies and violas are most popular due to the color range and profusion of bloom over a long period.
There are a few perennials that bloom mid-winter. Examples include bergenia, gazania, hellebores, and red-hot-poker (Kniphofia hybrids). Take a quick walk through the Ruth Storer garden at the west end of the UC Davis Arboretum to get some ideas; it is an all-season resource. On a recent visit the Kniphofia variety called Christmas Cheer was in full bloom.
Certain shrubs give us reliable winter flowers. Examples include the golden bush daisy (Euryops), laurustinus (Viburnum tinus), Oregon grape (Mahonia), rosemary, and the extra-fragrant sweet Victorian box (Sarcococca ruscifolia). Some winter-bloomers with special requirements include camellias and winter daphne. Well worth the effort, but ask before you buy.
We also enjoy the colorful foliage of a number of evergreen shrubs. Cold weather leads to interesting chemical changes within the leaves of certain plants, leading to bright pigments that are less obvious or missing in warm weather. Just part of the background shrubbery much of the year, these stand out in cold months. Examples include the common heavenly bamboo (Nandina domestica) and the purple hopseed bush (Dodonea viscosa purpurea).
One deciduous shrub with late-season color is Japanese barberry (Berberis thunbergii), whose leaves turn bright red in fall and then hang through December. It grows to five feet tall or so. A dwarf cultivar called Crimson Pygmy only grows to 2 to 3 feet tall and wide.
Colorful winter fruit is a bonus of citrus, and the hardiest one is also the most ornamental: the kumquat. Not everyone likes to eat the tart/sweet fruit. The peel is sweet and edible, the flesh is tart. So to eat a kumquat, you pop it in your mouth whole and chew it up. But even if you don't favor the flavor, you can appreciate the abundant bright golden fruit out in the yard. Kumquats are cold-hardy well into the teens, have fragrant flowers in the summer, and the plant has dense foliage and grows upright.
Many ornamental shrubs have colorful winter fruit, including natives such as Toyon (Heteromeles arbutifolia) and Coffeeberry (Rhamnus californica). There are great examples in the Arboretum near the road which goes to Mrak Hall. The non-native heavenly bamboo, mentioned above, also bears red winter fruit with the colorful leaves.
Is it ok to plant these selections now? Sure, if your soil is workable. Digging in muddy soil is bad for the soil structure. But one silver lining to our dry season is that soil can still be turned and proper planting holes can be dug. If not, just hold the plants in the pot until spring. Don't forget to water them if we don't get rain!
For statewide weather data, go to the UC Davis IPM web site and look for the "Weather, models, and degree days" link here. I use the Davis.A station.
