Posts Tagged: cold weather
Avocados in Your Garden?
Advice for the Home Gardener From the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Situation and Request: We have a male and female avocado tree likely ~2.5 years old (we moved to our new home in Moraga, CA ~1.5 years earlier) adjacent to each other on a slope. This past year, there was only one fruit albeit the size of a man's palm (greenish-black, Hass?). This year, although there were several hundred blossoms, the tree again bore one fruit. Presumably because of heavy rains early in the year (~60-inches per the St Mary's weather station), the leaves turned yellow/spotted black and fell off...but we do currently have a profusion of large green leaves. So what do I need to do to increase crop? is it a fertilization issue and/or inadequate N application? or is it the young age of the trees? Your feedback would be much appreciated as we were planning on planting more of the dwarf variety during Spring.
MGCC Help Desk Response: Thank you for contacting the UC Integrated Pest Management (IPM) Program with your avocado questions. They have referred your questions to us at the UC Master Gardener Program of Contra Costa County.
Another contributing factor, as you noted, was the timing of rain last spring, which could have damaged the flowers.
Another factor is simply the complexity of the pollination process in avocados. Avocado trees are not male or female, but having two compatible trees should lead to fruit production, if other factors you have mentioned are also favorable. Avocados have a type of flowering behavior known as "synchronous dichogamy" where the same flowers open in female and male forms at different times over 2 days. When flowers first open they are in the female phase. At the end of the female phase, which only lasts 2 to 4 hours, the flowers close. On the next day, flowers reopen as male and shed their pollen. To complicate matters even further, the time of day when the avocado flowers open depends on the variety. That is why avocado trees are typically planted in pairs and usually require a pair with one each from a "Type A" and "Type B" variety. For more information on avocado flowering and a table of complementary "Type A" and "Type B" varieties, see http://www.ucavo.ucr.edu/Flowering/FloweringBasics.html This complementary pairing should be a prime consideration for success if/when you plant more avocados, especially if you don't know your current avocado varieties.
You also asked about fertilization. Young avocado trees do need fertilization, primarily in the form of nitrogen. Three year old trees would need around 1/2+ pound of actual nitrogen per year. The nitrogen could be applied spread over 3 to 4 applications during the year. For information on fertilizing avocados considering age of the tree, please see http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/CULTURAL/avocadofert.html Note that while fertilization is important for the health of the trees, it will not counteract the possible pollination problems that you likely encountered.
For more information on growing avocados, you may also want to check out the cultural information and FAQs at this site: http://www.ucavo.ucr.edu/General/Answers.html#anchor1425068
Another good source of information on the growing and care of avocados is the California Rare Fruit Growers: https://www.crfg.org/pubs/ff/avocado.html.
You also mentioned that the leaves turned yellow and black and then dropped off last winter. That could have been from rain, but may have also been problems with insects or a form of root rot. Please get back to us if this happens again, so that we can help identify the problem.
One final note is that avocados are tropical trees that prefer temperatures in the 60 to 85 degree Farenheit range. While many varieties can tolerate temperatures outside that range, you may have trouble with the cold temperatures in Moraga. The fact that your trees were planted on a hillside could be an advantage for drainage and, if you are in a sheltered area, they may do well. The successful avocado growers usually are a combination of appropriate variety and the planting and protecting the tree from cold. If you are going to plant more avocados this spring, we suggest you especially consider varieties that can tolerate the colder temperatures of Moraga.
Finally, welcome to the “cult” of the home avocado gardener. Despite all the troubles trying to grow avocados in our less than tropical climate, there are always home gardeners who have successfully grown them. With some appropriate planning and care that will be you.
Good luck with your avocados.
Please let us know if you have further questions or want additional information.
Help Desk of the UC Master Gardener Program of Contra Costa County (ECS)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round (except the last two weeks of December) to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/)
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Cold Nights in Ventura
By way of Ventura grower Sandy Hedrick. This is a compilation of nights of "firing" done by Farm Advisor Bob Brendler from 1923 to 1988 that was collected by Terry Schaeffer of The Fruit Frost Service. Can you imagine over 70 nights of freezing temperatures when the smudge pots had to be lit? Now we don't normally "fire" the pots, but use water and wind more commonly. And it's only for a few nights at the most during the winter. In the "old" you couldn't plant avocado or lemon east of Sycamore Rd, just east of Santa Paula. Now there are avocados planted in Fillmore. And apple bloom erratically out there for lack of chill hours. And in summer it's getting too hot to grow strawberries even on the coast because with temperatures above 80 deg there is poor pollination.
Brendler loved weather information and irrigation issues. He was the first person in the Ventura office to use a computer and he was the oldest Advisor in the office at the time. The weather data chart was the first type of chart that could be done on a computer.
Do you think something has changed? By the way Terry is still running a private weather service for growers in Ventura.
Click on the link: Temp Chart002
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Can I Protect That Almost Ripe Orange This Winter?
Advice for the Home Gardener from the Contra Costa Master Gardener Help Desk
Client's Question:
Response from the CCMG Help Desk:
Thank you for your call this morning about your navel orange tree. Fruit should be harvested when it has developed full color and, most importantly, full flavor. Citrus turn color in fall when they are exposed to cold temperatures, but this does not affect the fruit sweetness. Navel oranges may not be ready to harvest until the late winter, and Valencia oranges are usually mature in the summer.
The best place to store the fruit is on the tree. Once you pick the fruit, it does not increase in sweetness or ripen more fully. Unfortunately, freezing temperatures don't care if your oranges are ripe or not! However, if you do pick the fruit, it will keep for about 4 to 6 weeks under refrigeration. (Note: Commercial orange growers basically use the orchard's trees as their warehouse making multiple pickings as they ripen. If a freeze is predicted, growers will usually pick all the oranges and sell them for juice).
For even further information on protecting citrus in the winter, I would recommend two publications "Frost Protection for Citrus and Other Sub-Tropicals" (http://anrcatalog.ucdavis.edu/pdf/8100.pdf) and “Citrus for the Home Garden in Contra Costa County”.(//ucanr.edu/blogs/slomggarden/blogfiles/4260.pdf).
Please contact us again if you have more questions.
Contra Costa Master Gardeners Help Desk
Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/
More Risky Business
If you’ve been reading our “Farming in the Foothills” blog over the last year, you’ll know that commercial farming is inherently risky profession. My fellow farmer Molly Nakahara (of Dinner Bell Farm) did a great job of describing farming risk in her October 28 post, “Farming, the Original Risky Business.” We farmers and ranchers face numerous uncertainties – from the weather to the marketplace to the regulatory environment. Some of these risks are short-term – like the snow storm that cancelled last weekend’s farmers’ market in Auburn. Some are long-term – like the potential impacts of new federal food safety standards on direct-market growers. Some risks can be eliminated, while others can only be mitigated. Our success as farmers and ranchers, in large part, depends on our success in managing these risks.
As a sheep rancher, there are two weather-related risks that foremost in my mind at the moment – one short-term and one long-term. As we wrap up our fall lambing season, we are in the midst of our regular early December cold snap. While the first week of December usually brings some of the coldest temperatures of the year, this year’s cold snap is especially severe and protracted. Since December 4 in Auburn, our morning lows have been in the teens, and our daytime highs have been in the high thirties or very low forties. At McCormack Ranch in Rio Vista, where we are lambing, the temperatures haven’t been much warmer. The cold weather presents a number of challenges: lambs that aren’t getting enough mother’s milk can quickly succumb to hypothermia. Lactating ewes that aren’t getting enough drinking water won’t produce as much milk. The sheep have to consume more feed just to maintain body temperature (let alone produce milk), so their feed demand increases.
From a longer-term perspective, we appear to be in the midst of a protracted drought. While we had a bit of rain in September, this fall has been dryer than normal. We finally got a germinating rainfall in mid-November – just in time for the weather to turn cold and the grass to go dormant. As a grass-farmer, I depend on fall grass growth to get our sheep through the winter months – and this year we didn’t get much growth. As we look toward next year, I’m very concerned that we may not have enough irrigation water to carry us through the summer months. The Nevada Irrigation District (NID) recently reported that we just experienced the driest January-November period in the district’s history – just over 20 inches of precipitation fell in NID’s upper watershed in the past 11 months. Unless we catch up soon, we may be facing reduced water deliveries next summer.
Obviously, these challenges can make for depressing conversations with other farmers, but there are some strategies we can use to mitigate (rather than eliminate) these risks. The weather is beyond our control, but our response to these conditions is not. Here are a few of the things we’re doing to manage these risks:
Short-term – sub-freezing temperatures
- As soon as we saw the forecast for sub-freezing temperatures, we moved the ewes who had not lambed into more sheltered paddocks. Lambs and ewes can deal with cold temperatures as long as they can avoid windy and wet conditions. These paddocks also had plentiful forage, which ensured sufficient feed intake for lactation and body temperature maintenance.
- We wrapped all of the pipes on the ranch to reduce the possibility of breakage (and subsequent time-consuming repairs). We also placed extra troughs in each paddock that we could reach with a hose from the water truck – if the permanent troughs froze, we could at least fill the temporary troughs from the truck.
- We moved the ewes with older lambs into the hills and increased the amount of hay we were feeding – again, to maintain milk production.
Long-term – drought
- We usually plan on culling 10-15 percent of our older ewes and replacing them with ewe lambs. We’ve been expanding our flock over the last several years, which means we cull fewer ewes and keep more ewe lambs. This year, we’ll consider culling more deeply – perhaps 20-25 percent of our ewes will be sold once we’ve weaned their lambs. We’ll also only keep ewe lambs out of our best and most productive ewes. While this will reduce our sheep inventory in the short-term, it will improve the overall productivity of our flock (measured in terms of lambing rate and pounds of lamb raised per ewe) over the long-term. Drought, then, allows us to improve the genetics of our flock.
- We’ll once again limit the number of lambs that we’ll keep to finish on grass and market directly to customers. As in 2013, we’ll base our decision on the amount of high quality summer forage likely to be available to us.
- We’ll evaluate the potential to invest in more efficient irrigation technology, like pod sprinklers. If we can make our irrigation water go further, we can grow more forage.
- Finally, we’ll also look for opportunities to graze alternative forages. This year, we’ve grazed crop residues and green “weedy” forage at Amber Oaks Farm in Auburn. We’ve also grazed alfalfa stubble in Rio Vista. Grazing helps to manage pests (plants and insects) on these operations while providing our sheep with higher quality forage.
Even with a risk management plan, these are the types of things that keep farmers and ranchers awake at night. While rain and wind never fail to awaken me from deep sleep, they keep me awake all night if they come in the midst of lambing. That said, a systematic approach to considering risk and adjusting to real-world conditions is critical to a successful farming or ranching operation. Ultimately, risk is just one of the many reasons that Tom Cruise isn’t a farmer.