By Julie Pramuk
In a recent UC Master Gardener workshop at our new Las Flores Learning garden we focused on dealing with the recent heat wave and its effects in our gardens. We outlined several topics to consider, with in- depth demonstrations and examples of:
- Healthy Soil components
- Water needs: too much or too little
- What does heat stress look like
- Right Plant, right place
Consider watering needs by locating plants needing more water closer to your house where you can monitor their water needs. Plants that can get by with less water could be placed further out on your property. Use separate valves for different watering needs. Water judiciously to avoid wasting water. Provide temporary shade for your plants with shade cloth, burlap, or some other covering for severe day or night temperatures. Using umbrellas or chairs is a quick and easy way to shade plants. Don't prune off dried or dead parts of your plants during a heat wave. Wait until summer ends and you feel safe to prune. The dried sunburned parts of plants act to shade the leaves underneath. Green parts of sunburned leaves will help the plant to photosynthesize and generate new leaves.
Plant in the fall or early winter when, hopefully, there is a promise of rain and plants can establish a good root system. Skip fertilizing in a heat wave. Plants can't spare the energy to take up fertilizer and the fertilizer may burn the roots. Remember to mulch, mulch, mulch your garden. Adding a 3-4 inch layer around your shrubs and trees will help keep the soil several degrees cooler and prevent your soil from drying out. Keep mulch 6 inches away from the trunks of trees. Finally, there are times when our gardens suffer for various reasons: an irrigation system breaks down or you are away for a time and you wonder if a plant or tree be revived. Give your tree or plants a chance to respond. After a freeze, for example, a tree or plant may need a season to recover. Be patient. Different plants have their own way of responding and healing just like humans.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Jane Callier
The UC Master Gardeners of Napa County have a series of documents of useful garden practices in their Healthy Garden Tips collection, including microclimate documents listed below.
Information Links:
Healthy Garden Tips
Right Plant, Right Place https://ucanr.edu/sites/ucmgnapa/files/153367.pdf
Cool Season Gardens for Napa County https://ucanr.edu/sites/ucmgnapa/files/153368.pdf
Creating Microclimates in the Garden https://ucanr.edu/sites/ucmgnapa/files/153509.pdf
Climate Zones Map of Napa County https://ucanr.edu/sites/ucmgnapa/files/254550.pdf
UC Sonoma County-Right plant right place
https://sonomamg.ucanr.edu/Sustainable_Home_Gardening/Right_Plant_Right_Place/
UC IPM-dealing with thermal injury or high temperatures
http://ipm.ucanr.edu/PMG/GARDEN/ENVIRON/thermal.html
by Carole Kent
The power of caring and acting, and I emphasize EVERY action to care for the Earth (capital E) and earth (small e) is necessary and important. Greta Thunberg, the young climate activist from Sweden puts it this way, "no one is too small to make a difference".
Climate change is obvious and it affects everything. We can all work to stop and reverse this damage, and it all begins with soil. We can cultivate an attitude of caring and relationship with soils as we understand more about the life of the soil.
Healthy soil is teeming with life: approximately 8 billion microorganisms live in 1 tsp. of soil. Healthy soil has highly complex and organized relationships where everything is connected. Carbon is essential to all life and carbon use and sequestration is out of balance. By improving the health of our soil we help correct the imbalance, at the same time strengthening plant's ability to withstand increasing heat. Plants draw down and sequester carbon, carbon helps feed the microbial life in the soil which helps feed the plant, a true win (slowing climate change), win (feeding the microbes), win (feeding the plant).
There are many ways to increase soil health with innumerable benefits:
- Increase soil organic matter: All types of soil benefit:sand, clay & silt, because organic matter increases water retention,4" of compost can decrease water use by 40%, and compost attracts and feeds soil microorganisms.
- Keep soil covered: It can reduce soil temperatures dramatically, reduce evaporation, reduce weeds, reduce compaction and erosion.
- Practice judicious water use: Water in early morning and use drip irrigation, it reduces evaporation and places water next to roots
- Avoid chemical fertilizer and herbicides and pesticides: Chemicals kill the life in the soil, birds, bees, beneficial insects, leach into streams and lakes, contaminating water sources
- Maximize living roots, plant cover crops: Soil organisms need to be fed carbon, carbon comes from plants roots, roots enable carbon sequestration
- Increase plant diversity: Nature loves diversity, monocrops invite pests and disease. greater diversity above ground increases diversity below ground
- Minimize soil disturbance-no till: Disturbing the soil destroys the life in it and breaks up the soil food web, requiring rebuilding of fungal hyphae that link plants sharing water, nutrients and warnings of pest invasions. It breaks up aggregates and releases carbon into the atmosphere, allows water to evaporate and brings up weed seeds and creates hard pan
- Avoid soil compaction-don't walk on soil: It squeezes air out and soils have less ability to hold water, and thus can cause erosion
Our future depends on us taking action. Taking action depends on knowledge, caring and being aware that everything is connected. We are part of, not apart from this magnificent web of life. Deborah Koons Garcia, a documentary filmmaker says, "soil is one of the true miracles of the planet and we treat it like dirt."
Our calling is to change that.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Opensource image
Information links:
UC ANR Healthy Soils for California https://ucanr.edu/sites/soils/
Healthy Soil Basics https://ucanr.edu/sites/soils/Soils_101/
Tips to improve your garden soil https://ucanr.edu/sites/soils/Soils_for_Homes_-_Gardens/
Soils and Nutrients https://ucanr.edu/sites/Soils_and_Nutrients/
Cynthia Kerson
With the weather getting warmer by the year, it's time we recognize the difference between heat and water stresses in our plants. The temperature is averaging 83°, and according to www.GreenCastOnline.com, a service provided by a fertilizer company, soil temperatures have been averaging about 81° in Napa and 85° in Calistoga. Lately, these temperatures have been as high as 84° and 88°, respectively. This company wants to sell you lawn fertilizers, so their warning system is in place to alert when certain weeds or insects might appear because the soil of your lawn reaches the temperature they thrive in.
Most of the plants we grow in our gardens like the soil temperature to be between 65-75°. When the soil gets too hot, they mitigate the effect by wilting, bolting, getting sunburn and dropping leaves. What is the most common, knee-jerk, reaction to this? Water, water, water. However, hot soil and air temperatures don't always correlate with not enough water. In fact, too much water in the soil could contribute to the problem by suffocating the roots, so it's important to recognize the signs of heat stress and manage that. The first line of action is to mulch. I'm sure you've heard a Master Gardener or two assert the importance of mulching. Mulched soil (bark, hay, rocks [sometimes], and leaving leaves), are all forms of mulch. Unmulched soil generally follows the fluctuations of the air temperature and this is especially true in raised beds. Mulched soil tends to stay consistent throughout the daily cycle.
Another way to cool the soil, and hence the plant, is to provide shade cloth, which can cool the air by as much as 10°. In this case, since you are cooling, and not trying to protect from frost, leave the sides open so air can circulate but is cooler due to shade protection of the sun. This will also keep the humidity level constant.
How are heat and water stress different? The most common sign for both too much and not enough water is yellowing of leaves. Mottled leaves can also be a sign of either. The gardener needs to look beyond these symptoms to decide which it is. Overwatering may be expressed by droopy, floppy leaves that will become lighter green than the natural color of the plant's leaves, whereas under-watered plants wilt from the stem and may lose leaves.
When overwatered, the droopy stems occur because the plant loses turgidity. Turgidity is the pressure against the plant's cell walls from the amount of water within them, causing them to be erect, like a water balloon. Without enough water to support the shape of the cell, they'll flatten, or become flaccid, and when enough cells have lost shape, the stems wilt. This is the most obvious sign to determine whether the plant is under- as opposed to over-watered.
An overwatered plant may also shed leaves – but for a different reason: this is because the roots may be experiencing rot due to limited access to oxygen and nutrients in the soil. If you see this, obviously don't water more. Removing the plant and running the roots under water to clean them, removing severely damaged roots, and repotting or replanting is your best, albeit not guaranteed, way to resolve root rot.
A sign of an under-watered plant is leaf drop. Before they drop, though, their tips may brown, and they'll look dull and lack-luster. The plant will put more energy into survival and less into leaf and blossom development. If chronically under-watered, the leaves won't grow back. If intermittent, the leaves will cycle through starting and dying off. Obviously, the resolution is giving the plant water, but in doses. Don't flood the plant out of guilt. Water until you feel wet soil at about 2” depth and remain on whatever schedule works to maintain that level. Removing any blooms or imminent blooms will help the plant put its resources into preparation.
Knowing whether a plant is thirsty, drowning, or experiencing heat stroke is vital to its care. Recognize heat stress and resolve it by maintaining a healthy layer of mulch, covering with shade cloth, or possibly moving the plant to an area where the soil can remain cooler on hot days. If watering is the issue, respond with the appropriate measures discussed above. Hopefully your plant will come back and thrive.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Diagram: https://qsstudy.com/turgidity-definition-importance/
Reference: OSU extension-heat stress https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/heat-wave-garden-how-identify-prevent-heat-stress-plants
by Cynthia Kerson
As usual we toured two gardens. First, we enjoyed a lovely garden setting in northeast Napa. In driving up to the house the owner showed us a stand of conifers recalling the years the property was a Christmas tree farm. One MG recalled the annual fights with her brother over which tree they would take home. It also retains some trees from the 2017 fire, showing just how close that fire came to their home.
Thinking it would be hard to beat, off we went to the next garden. Once crossing a bridge off Silverado Trail and heading west, we land at the next property. The owners built their ecologically-sound home only a few years ago, installed a natural pool and surrounded it with water-loving plants, such as taro, iris, and Bacopa monnier ground cover. The pond was stocked with fish, including shubunkin to help with cleaning. Unfortunately, because the property butts up to a creek, the fish have also been enjoyed by the local river otter.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Cynthia Kerson
Our fourth and final report for the 2022 season is of a small family vineyard in west Napa and a lovely garden in a well-established Napa subdivision.
Information links:
UCMG SLO-Milkweedhttps://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=30231
UC ANR-The California backyardhttps://homeorchard.ucanr.edu/Fruits_&_Nuts/
UC IPM-Aquatic pest controlhttp://ipm.ucanr.edu/IPMPROJECT/ADS/manual_aquaticpestcontrol.html
UC ANR-Recreational ponds and lakes ppthttps://ucanr.edu/sites/Mariposa/files/103180.pdf
UC ANR.EDU-repository-Weed Control in Irrigation and ornamental Ponds https://ucanr.edu/repository/fileaccess.cfm?article=161360&p=PVEIMA
by Bob Niklewicz
Did you know... There are over 600 muscles in your body?
Dia. 1: The muscles attach on either side of each joint. Muscles only pull (contract/shorten) and, when they do so, they move the joint in one direction. Muscles do not push a joint. The muscles exert force by contracting to achieve motion. The muscle can generate the most power in its intermediate range. This middle range is often the neutral position of the joint.
Muscle components: Think of it like a co-axial cable with thousands of fibers. Each has its own nerve and blood vessels It attached to the bone via a tendon.
There are different types of muscle:
Dia. 4: The smooth muscles contract around your blood vessels and your intestines.
Skeletal muscles produce locomotion and are tubular and in bundles. For the purposes of this article, skeletal muscle function will be our only concern. With a hard skeletal muscle contraction, 60% of the circulation can be cut off from the nutrient pathway that will lead to fatigue.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Diagrams: Vecteezy.com