- Author: Chris M. Webb
Our Ventura County UCCE Master Gardeners work hard delivering science-based gardening information to the public. One of the ways they accomplish this is through their MG Speaker Bureau. The speakers are very knowledgeable in their subjects and are available for group meetings.
The current topics offered are:
- Container Gardening
- Container Vegetable Gardening
- Fruit Gardening
- Garden Design/Plant Selection
- Gifts from the Garden
- Introductory Horticulture
- Pest Management
- Water-Wise Gardening
- Low Cost/No Cost Gardening
- Low Maintenance Gardening
- Tomato Culture
- What About Soils?
- Succulents and Cacti
- Vegetable Gardening
- What is a Master Gardener?
- Peppers, Onions and Tomato Facts
- Fertilizer Use
- Weed Killers
Additional information and instructions on how to request a speaker can be found by clicking here. Please contact our office if you need additional information.
- Author: Chris M. Webb
Like the rest of our researchers, Ventura County UCCE Farm Advisor Oleg Daugovish and Staff Research Associate Maren Mochizuki are busy with many projects. What will be shared with you today is a summary of one of Oleg and Maren’s projects that have the potential to increase agricultural yields using captured greenhouse gases.
More than 7 billion tons of green house gases (GHG) were released in the United States in 2006. Most of the gases are attributable to the combustion of fossil fuels used for electricity and transportation. While current CO2 capture technology focuses on geological storage, an incentive to capture emissions may be offered by agriculture: CO2 could be supplied to plants for uptake and sequestration as an alternative to underground storage. Agricultural plants with C-3 carbon assimilation pathway have shown increased productivity at CO2 levels elevated above the ambient air concentrations. One plant that has such a pathway is the raspberry, which is the fastest growing high value crop in Ventura County (annual value ~$85 million) and appears very suitable for carbon dioxide sequestration: it is a perennial C-3 crop with multi-layered canopy, is grown in tunnels/hoops that protect the CO2 delivery to leaves from wind and rain, and, has existing support structures for the gas delivery system.
Working with collaborators, we evaluated several plant productivity parameters such as fruit yield, berry size, cane size in a large scale replicated study.
The delivery system was successfully designed and installed, applying a total of about 60 tons of CO2 to three specific hoops during the four-month trial. Diurnal measurements of leaf stomatal conductance, CO2 assimilation, and fluorescence showed a mid-day depression, enabling us to make an informed decision about optimum application time. We avoided application at the time of the day when plants would be unable to take up the applied CO2, thereby minimizing waste. We found CO2 concentration in the hoops where gas was applied were 20-25% higher than ambient CO2 concentration during delivery periods (8 h/day), generally returning to ambient levels during hours when gas was not applied. We also found that leaves in the middle and lower canopy, rather than the top, were the most active, prompting us to place our CO2 drip tape for delivery at about 90 cm (35 inches) above ground level.
The number of baskets from the full hoops in which CO2 was applied increased by 36% after CO2 application. Berry weight also increased 0.1% per berry in the CO2 hoops. Cane height, number, and diameter as well carbohydrate content of fruit were similar after CO2 application in all measured plants.
Further information about this study can be obtained by contacting our office.
- Author: Chris M. Webb
So you’d like to plant a vegetable garden but you don’t have room at home? Or maybe you do have room at home, but would enjoy some camaraderie while you plant and harvest? Community gardens can be a great solution to either of these situations.
Ventura County has lots of opportunities for those who would like to have a plot at a community garden. On the Ventura County UCCE website we offer a guide to local gardening resources, which can be found here.
In addition to available garden plots, this resource also includes contact information for groups such as the Grow Food Party Crew and the Ventura City Corps that assist others in establishing their own gardens. The UCCE Master Gardener Speaker’s Bureau is another great resource and is available for talks to groups on a variety of subjects.
Several local food banks are a great place to take your excess harvest. The food banks in turn can quickly deliver the fresh fruits and vegetables to outlets throughout our community for those in need. Local food bank contacts are also available in this resource.
Lastly there are many places one can find locally produced compost and mulch. David Goldstein, an environmental resource analyst for the County of Ventura explains the difference between compost and mulch in addition to providing details on how the products are produced. He also includes contact information to find locally produced compost and mulch -- some is free, and the costs of the others vary. Some places can even deliver directly to your home or community garden for an additional fee.
- Author: Chris M. Webb
The following home garden water conservation tips were written by Ventura County UCCE Farm Advisor Ben Faber. This article and other practical pieces for home gardeners can be found on this section of our website.
When to water? How much to water? These are two very important questions that need to be answered before watering lawns, shrubs, trees, and vegetable gardens if we want to provide the most beneficial use of this resource. Because of variability in plant size, weather (temperature, wind speed and direction, humidity, clouds and fog), types of soil and water, and the method of watering, it is difficult to give one recommendation that is true for all situations. Additionally, watering plants on a fixed schedule subjects them to periods of too much water and at other times to drought, because weather and plant size change. A young avocado tree in December may use only one gallon per day while a 20-foot tree in August might use 35 gallons per day.
The following are general principles. As plants increase in size, rooting becomes deeper, and the frequency of waterings can be decreased because more water is stored in the larger root zone. The time to water can be determined by the appearance of the plant, by the soil moisture content, or by estimating the amount of water used since the last irrigation.
. In most cases, plants can wilt slightly at midday before it is necessary to apply water the following day. Alternatively, i if you dig with a trowel or shovel down to 1 ft depth and find the soil is dry, then this might be used as an indicator of the time to water.
Soils and Water
In similar climates, water use by plants generally is the same regardless of the soil from which it is taken; however, soil variability is important in watering. A sandy soil requires more frequent, short watering than a clay soil to prevent water loss beneath the root zone. With heavy soils, it is best to water less frequently because these soils will hold more water. Heavy soils typically do not absorb water rapidly, so to avoid runoff it may be necessary to split the watering times into two or more periods. Adding organic matter to clay and sandy soils will increase the rate of water penetration in day soils and the water-holding capacity of sandy soils.
Other than seedlings, which are shallow-rooted, water should be supplied to a minimum depth of 1 ft in the soil (approximately 1 inch depth of water on the surface of the soil will infiltrate down to 1 ft). An area 10 ft x 10 ft will require about 62 gallons of water to filter down to 1 ft. This would be similar to 1 inch of rain or lawn sprinkling on the same 100 sq. ft. Infrequent but deeper watering will result in a deeper rooting system, and the plant will be better able to sustain periods of high water demand. Less frequent watering will also minimize loss of water by evaporation from the soil surface.
During or after a watering, the depth to which soil moisture has been restored can be determined by probing the soil with a metal rod not more than 3/16 inch in diameter. A big screwdriver is also a good tool for probing. The force needed to push the probe will increase suddenly when it reaches dry soil. The length of time of sprinkler operation or amount of applied water that was used to achieve a certain soil depth can then be used as a standard for future waterings.
Trees and Shrubs
In a winter with adequate rainfall, the whole root zone is filled with water near the end of the rainy season; however, in dry winters, plants need supplemental watering. The amount of water to apply is the amount required to replace the water taken from the soil by roots and lost by evaporation from the soil surface since the last rainfall or watering. Water to a depth of 2 ft (approximately 2 inches of water or 125 gallons per 100 sq. ft) under the drip line (canopy) of the tree or shrub. With deeper-rooted trees, for every third watering, apply twice as much, or four inches (250 gallons per 100 sq. ft). This will ensure that the deeper roots will be maintained and that various salts in the water are leached from around the roots.
Ideally, water applied to trees and shrubs should be ponded at the site by building berms around the plant. This insures that the applied water goes directly to the plant and is not wasted. It also makes it possible to visualize 2 inches of applied water. For trees it is best to build two berms: one 6 inches high, located in a 1 ft radius around the trunk and a second following the drip line of the tree. The interior berm is created to prevent diseases caused by water standing around the trunk of a tree or shrub. For trees located in lawns,
&water bubbler at the base of the tree can be used to deep water the tree, without applying excess to the lawn.
Because roots of trees and shrubs often extend in all directions far beyond their longest branches and comingle, it may not make sense to water them individually. A more practical procedure may be to create dikes around a group of these plants. The total impounded area of each basin should not be greater than 50 sq. ft and the surface within should be as level as possible. The 50-sq. ft area and levelness will encourage an even distribution of water to the various plants.
Depending on the hose diameter and water pressure, many household hoses apply about 5 gallons per minute. So to apply water with a subsoil irrigator to a tree with a 10-ft-diameter canopy, it is necessary to run the water for 25 minutes (2 inches of water on 100 sq. ft = 125 gallons). The bubbler should be moved every five to ten minutes around the tree so that all the root zone is watered. Since the 5-gallon-per-minute rate is an average, one’s own situation can be measured by filling a five-gallon bucket with your hose and timing how long it takes to fill.
Vegetables and Flowers
Vegetables or flowers can be grown in sunken beds or level basins that can be flooded in the same fashion as trees and shrubs. Sunken beds should not be larger than 50 sq. feet so that they can be filled rapidly to achieve uniformity with the depth of water to be applied. Furrows also can be used in growing flowers and vegetables. Spacing of the furrows should be such that water from the furrows wets the whole bed. The spacing of furrows will vary with soil type. Sandy soils need closer spacing to avoid loss of water out of the root zone when trying to wet the whole bed, while clay soils can have wider spacing. The amount of water applied by furrows is the amount needed to move across to the center of the bed. By probing with a stick or trowel in the center of the bed, it is possible to determine the depth of water and the amount of time needed to continue to run the water. Canvas soaker hose or drip tape are also good ways to water beds. The length of time to run them can be determined by using the calculation used for trees or simply by probing the soil to find the depth of water infiltrated.
Studies by the University of California at Riverside have demonstrated that many turf grass species can get by with as little as 60% of optimum watering with little stress. Most lawns have areas that dry sooner than other parts of the lawn. Let these areas be your indicator for watering the rest of the lawn. When the grass in the dry area becomes dull colored and does not spring back when stepped on, water the entire lawn. The amount or length of water application should be enough so that a stiff metal rod or screwdriver can be pushed 1 ft into the soil. This depth for most soil textures represents about 1 inch of rain. Alternatively, cans can be set out in the lawn, the system turned on, and the length of time it takes to collect an average of 1 inch of water can be used in subsequent waterings. This test will also show how evenly water is being applied and can suggest ways to correct sprinkler performance.
Sprinklers should be run so that no runoff occurs. If water has not penetrated to 1 ft and runoff occurs, turn the system off for an hour then turn it back on to apply the needed amount. Spading or aerating lawns can help water penetration.
Some Do’s and Don’ts
Select plants that are adapted to warmer, drier climates.
Adjust sprinklers for uniform water distribution.
Fix leaky faucets and lines.
Water early in the day to reduce evaporative loss.
Mulch beds to reduce evaporation from the soil surface..
Shelter container plants from winds.
Don’t sprinkle during windy or hot periods of the day.
Don’t put the water on the street and sidewalk; put it on the plants.
Don’t use softened water (sodium treated), if it can be avoided; it will harm most plants.
Don’t put sprinklers on a timer that is not adjusted with the weather; failure to adjust your timer assures you of wasting water.
- Author: Chris M. Webb
Ventura County UCCE Farm Advisor, Ben Faber shares with us his knowledge of avocados.
The avocado is an unusual beast in many ways. And flowering is no exception. It follows what is called synchronous dichogamy. The flower has both male and female parts, but those portions open at different times, opening first as female, closing and then opening as a male. It does this over two days, so in effect it can not pollinate itself.
To make it more interesting there are what are called A and B varieties. These varieties open and close in a different pattern, so that there is some overlap between the male stage of one variety and the female stage of another variety. This is how you get cross pollination.
This sounds really good as a model, but most avocados haven’t read the book: for a given variety, there are always some laggards with both female and male stages on the same tree.