Monday, December 19, 2011

Integrated Pest Management

Integrated Pest Management (IPM) is a pest control method which incorporates ecological principles into pest management practices. Gardens are full of insects, some are considered beneficial because they act as pollinators, decompose organic matter, or eat pests. However many of the critters and insects in gardens are considered pests, which the IPM program of the University of California defines as "organisms that damage or interfere with desirable plants...(they) also include organisms that impact human or animal health."

In the picture below you will find a lady bug and several aphids. Aphids are soft-bodied insects that feed on the sap of plants; they are considered pests because they damage the ability of the plant to provide nutrients to its leaves. Aphids also accumulate rather quickly, so if one is found, many more will follow. Luckily, aphids can usually be removed by spraying them off with water or hand picking. Larger infestation issues can be resolved with homemade garlic or pepper sprays.

Photo of ladybuy and aphids courtest of Dave Gunn
IPM is a targeted approach to reducing pest populations and is based on the following principles and techniques:
1. There is an acceptable level of pest population. Prior to commercial agriculture many farmers accepted that they would lose a small percentage of their yield to pests. Over time, the standardization of more potent pesticides and elaborate applications (such as crop dusting) changed the expectation of commercial farmers. IPM developed as an alternative to widespread pesticide use in the 1950s throughout the US, when indiscriminate field spraying began to occur on commercial agriculture sites.

2. Preventative cropping and cultural practices. There are several techniques that gardeners can do to reduce pests naturally. A method called intercropping places different plant species next to each other in the garden, rather than planting the same species together. A variety of bugs will be attracted to the different plants, reducing the possibility of an invasion. Plants that attract beneficial organisms (those that deter or eat pests) should be planted throughout the garden. Another method to reduce pests naturally is to plant peppers in between plants. Pepper plants are high in capsaicin and are helpful in deterring mammalian pests.

Photo of habanero peppers courtesy of Amy Kay Watson

3. Monitoring. Monitoring is the key to success with IPM practices. Careful observation and identification of which species are harming the garden will allow the gardener to determine the best method of pest control.

4. Appropriate control mechanisms. There are essentially three control mechanisms used in IPM: mechanical, biological, and limited pesticidal controls. When pest populations are low and localilized, mechanical controls (such as hand-picking or water spraying) can remove pests best. Biological controls include the use of natural sprays, intercropping, and incorporating plant species that attract natural enemies of pests. Finally, limited pesticidal controls are used when both mechanical and biological controls have failed. A targeted application of a pesticide may be used to reduce the pest population.

You can practice Integrated Pest Management in your school's garden. In late January/early February, start planning your garden. This is easily done by tracing an outline of your planting area and creating symbols for different plants. Incorporate the concepts of intercropping into your garden design. Also, try to include nectar-producing plants which tend to attract a variety of pest enemies naturally. Other plants to try: marigolds, peppers, and garlic.

For a list of plants to combat particular pest species see:

For more information on IPM:

The Radish Density Experiment

Radishes are the edible root of a rapidly germinating plant of the Brassicaceae family. In fact, the word radish derives from the Greek word Raphanus, which literally means to "appear quickly". Most radish varieties take 25-30 days to mature from seed to full-sized root. Like many edibles in the Brassicaceae family, they also thrive in cooler temperatures, making them the perfect seed to use in a winter experiment.

Photo of radishes courtesy of Allison P. (Worldharmony)


This experiment should help students understand the ideal population densities for radish crops and prompt them to hypothesize how nutrient uptake and availability is impacted by population density.

-Population density (plants): Can be defined as the amount of plants contained within a spatial parameter (e.g. the number of radish plants in one square foot). Population density studies are often referred to as "crowding" studies. In this case we are examining plants, but population density is a ubiquitous topic in biology and can refer to any organism, even humans.

-Nutrient uptake and availability: Refers to the amount of critical elements, such as carbon, nitrogen, phosphorous and potassium, as well as water and sunlight, that are readily available to the plant and the ability of the plant to procure those elements from the environment. Uptake and availability can be severely impacted by plant density as competition between plants increases with higher densities.


To do the experiment you will need radish seeds, a planting area with at least 24 square feet (this can be noncontiguous-raised beds or pots are fine), a ruler, and a scale.

-Section off six 2 ft. x 2 ft. areas, for a total of six 4 sq. ft. sections.

-Two of the 4 sq. ft. sections will be used for 1-inch planting densities, two sections will be used for 2-inch planting densities, and the remaining two sections will be used for 4-inch planting densities.

-Use the ruler to help you plant seeds and space them according to the image below. If you are planting the 4-inch density section, make sure each seed is equidistant from the other seeds. Use the image below as a guide:

-Once the seeds are planted, be sure to water each section at the same time and with the same amount of water. You can also use the planting guide on the back of the seed packet to identify ideal watering and planting conditions.

-Take notes on how the plants grow at one week intervals and use these observations to hypothesize which planting density is best for radishes.

-After thirty days, make your final observations about the growth of the plant and pull the radishes, but be careful to keep each section separate.

-Next, weigh each section individually using a scale and record your values.


Based on your findings, can you determine which density was ideal for radishes? How did your hypothesis based on your observations differ from your final results? Did the density of the radishes appear to have any effect on the weight or total amount of radishes in each section? Were the findings between similar sections identical or did they vary?

Dormancy and Vernalization

Over time many plants and trees have developed strategies to protect themselves and to thrive in their particular climate. Two such strategies, which usually occur in tandem are dormancy and vernalization. Dormancy refers to a period of time when the organism physically stops growing; this is typically done to conserve energy during the colder months of the year or to protect itself from adverse environmental conditions. Plant and tree dormancy that occurs in response to environmental conditions is called consequential dormancy, and predictive dormancy occurs when an organism's natural biological cycle anticipates a weather change and promotes dormancy in advance. During dormancy deciduous plants will lose all of their leaves and evergreens suspend growth. The picture of the white birch tree below shows a dormant tree that has lost its leaves and is essentially "hibernating" through winter.

Photo of dormant white birch tree courtesy of Jilly Clardy
Vernalization refers to the period of cold weather exposure experienced by plants and trees, which actually enables them to set buds and produce fruit when warmer temperatures arise. To clarify, dormancy refers to the suspension of the organism's growth in anticipation or response to environmental change, while vernalization refers to the plants ability to set flowers or produce fruit after dormancy in a direct response to cold weather exposure. If you have stone fruits like peaches and plums or even apples, these all need a vernalization period for them to be able to bear fruits. This is why it is more common to see stone fruits and apples in the Inland Empire than it is too see them along the coast.

Vernalization was discovered after many years of observation by agronomists and plant physiologists. A pioneering researcher in this field, Russian agronomist Trofim Lysenko, coined the term 'vernalization' and he also developed methods to manipulate plants which require vernalization to induce early production by artificial exposure to cold temperatures. In fact, Lysenko is credited with saving millions in Russia during a long, cold winter by being able to germinate winter wheat crops ahead of schedule, making food available in the spring instead of the summer.

*You can observe the process of dormancy at your own school. Take a few moments to observe the plants and trees in the garden and note which have lost their leaves and which have not.

*In one of our previous posts we discussed the citrus tree and its unusual characteristic of fruting in winter while many plants are dormant. Do some research to determine if, or when, the citrus tree experiences dormancy.

For more reading on dormancy and vernalization, please see the following websites:

Wednesday, December 14, 2011

Winter Fruiting Citrus Trees

Photo Courtesy of Andy Jien
In a previous blog post, we talked about two of the few fall fruiting trees, Persimmons and Pomegranates. Today's blog will be about citrus trees, some of the few winter fruiting trees. Citrus is a commonly used term that refers to several of the flowering varieties of the genus Citrus; the fruiting trees included within this genus are: lemons, limes, oranges, grapefruit, tangerines, and most species of kumquats.

Some of the earliest species of citrus trees are believed to originate from Southeast Asia near the area bordered by Myanmar (Burma), Northeast India, and the southwest corner of China (Yunnan province). Citrus trees were brought over to Europe from Asia and many of the citrus trees we see in California are decendents of the ones grown in the mediteranean regions of Europe. Citrus trees were commonly grown throughout Southern California around the turn of the century and well into the middle of the twentieth century; in fact, citrus fruit production is what attracted many of the first settlers to the Inland Empire and Orange County (appropriately named after the orange). Throughout human history, citrus have been cultivated and revered not only for their culinary properties, but their health benefits as well.

Citrus trees come in many different sizes and colors. There are standard varieties which grow to be approximately15-25 ft. in height, semi-dwarves are roughly between 8-15 ft. tall, and dwarves (which are the variety at most of the IEUA's school gardens) are about 4-8 ft. tall. Citrus trees begin to flower in the fall and by December most of their fruit have developed. They need a diurnal winter to change color, so our Mediterrenean climate is perfect for witnessing some of the beautiful colors of some citrus species. Some citrus trees grown in tropical locations never experience cool temperatures, which makes them stay green year round even when ripe.

If you live in an area that is near the Inland Empire Utilities Agency (Chino, Montclair, Ontario, Upland, Rancho Cucamonga), then it is likely that citrus trees have played a role in your city's history. As a fun project, have your students research the role that citrus played in your city. Try to find out which species of citrus were grown in your area and by whom.

For more reading on citrus and its role in Inland Empire history, please see the following websites:                   Time line of Citrus in the Inland Empire:

Los Osos High School is Moving Strong!

Volunteers trenching for irrigation.
Los Osos High School in Rancho Cucamonga is definitely a new type of experience for me in terms of administering the garden installation. While normally when we have volunteer workdays, we'll have a LOT of people attending, either a lot of kids or a lot of adults or both. Los Osos hasn't had very many volunteers. Interestingly though, they are quite dedicated to getting their garden installed. Even with only about 5 volunteers per workday able to attend, they've been moving at just about the same pace as the other schools with 20 - 30 volunteers.

Volunteers installing mediterranean herbs
 We've manage to be able to install about 50 plants, including 5 fruiting trees. We've installed all the underground irrigation for the site, and we've built six vegetable boxes and filled them with soil.
Volunteers building vegetable boxes.
 Not very many parents and teachers have been able to attend, but the few that have have been extremely helpful. Here we have a substitute teacher building vegetable boxes with his son.
Ms. Dolce installing the first plant, a navel orange.

Here is Ms. Dolce planting the very first tree of the garden just before thanksgiving break. This is a Navel Orange, Ms. Dolce subsequently installed all of the fruiting trees in the garden.

Monday, December 12, 2011

Rainy Season Runoff

Photo courtesy of Roger Mommaerts
 The rainy season in southern California occurs between the months of December and April, although we occasionally experience rain in May and June. The average precipitation of rain in southern California is about 12", with the majority of rainfall occuring in the month of February.
Although rain is not plentiful in southern California, especially compared with the majority of the United States, we do receive enough water that it can be harvested and stored for later use.

In fact, one way to conserve water and to help your garden grow is to capture rainwater on site in a rain barrel so it can be reused later during drier months.

Rain barrels can be purchased at your local garden or home improvement store. They are easy to install as you can see from the picture, but all rain barrel systems are different so read the directions before you start the installation.

Most rain barrel systems attach a hose to the rain gutter on the side of your house or building. Water is then diverted directly into the barrel. Barrels range in size from 50-60 gallons, so they can hold quite a bit of water and become very heavy.

One of the greatest benefits of installing a rain barrel is that you offset your potable water demand and do your part to conserve water. It also conserves water by recharging the rain water into the ground instead of running off into storm drains.

Friday, December 9, 2011

Upland High School Completed!

Avocado and Citrus at Upland High
 Well we finished the garden at Upland High(we actually finished in November). Here are a couple of photos I wanted to share with you all.

Upland High planted, a lot of fruit trees: Citrus, Avocados, Persimmons, Figs, and Pomegranates, all of which are drought tolerant and climate appropriate. They also received 14 vegetable beds. Because they only received a few trees and mulch we allowed for them to make up the rest of the grant in vegetable beds.

Vegetable beds at Upland High

Once we receive permission to share the photos of the kids working in the garden, we'll share them with you on this blog. Stay tuned for a dedication date as well! It was a lot of fun working with Mrs. McAdams and Mr. Whieldon and their students on this project.

Monday, December 5, 2011

Santa Ana Winds

PhotoSource: //

Southern California's coastal and inland areas are known for their mild weather patterns and mediterranean climate. However Southern California does experience certain unique weather phenomena, one of which is the Santa Ana winds. The Santa Ana winds are warm (sometimes hot), dry winds that sweep across Southern California and Baja California usually during the fall and winter seasons.

Santa Ana winds originate from the desert and flow in a southwest direction toward the sea. This is an unusual wind current as most breezes blow in an easterly direction. During cooler seasons, high pressure begins to build up in the Great Basin (western Nevada) and the temperature starts to drop. The cool, dense air is forced east to lower elevations where it begins to pick up speed and simultaneously increase in temperature as it passes through the Mojave Desert. Santa Ana winds can be very destructive as they can easily reach 40-70 mph. By the time they reach the larger population nodes of the inland valley, the air is hot and extremely dry. These conditions can intensify fires and cause severe damage to property and life.

Although it has several destructive characteristics, the Santa Ana Winds are here to stay. They preceded human settlement in this area and it is imperative that we learn to adapt to this weather phenomenon. If you have a garden with young trees, reinforce their trunks by tying a straight stake or pole to the tree. Also, if you're growing a vegetable garden, be sure to water regularly as the dry winds can damage crops.

Article sources and additional information can be found at: