By Penny Pawl, UC Master Gardener of Napa County
Winter isn't over, but in my garden it feels like spring has sprung. This is my favorite time of year. I discovered a bearded iris in bloom today, two months early and a great surprise.
The first thing on my to-do list in February is to weed. The weeds loved those early rains and now it is warming up. They need to be removed before they go to seed.
One weeding tool that works well for me is a weed torch or flame weeder made specifically for gardening. It uses a propane tank and a wand. You wave the flame over the weeds to kill them. It works best on small, young weeds growing in hardscape or gravel, and it doesn't damage the soil as many commercial herbicides may do.
Don't use a weed torch during dry spells or on hot, windy days. Keep the flame away from dead or brown material or flammable items like fencing. Wear sturdy shoes and have water nearby to stop any possible flare-ups. Some areas have bans on flame weeders, so check with your local fire department before investing in the equipment.
It's not too late to do sheet composting for weed control. You can find a lot of information about this method online. Basically, you are smothering the weeds by covering them with sheets of cardboard. If you want to plant something before the cardboard has decomposed, just cut a hole in it and dig your planting hole.
One year I experimented by planting half of my broccoli seedlings in soil covered by cardboard and the other half in uncovered soil. The plants in soil covered by cardboard did better.
If you haven't already done so, it's time to prune roses, fruit trees and other shrubs and trees. You can control growth better if you prune before the leaves and flowers come out in the spring.
Plant any bare-root trees and roses now. Remember to water them as they settle into their new home.
We know that drought conditions may continue so keep that in mind when planning your garden this year. Look online for information about the water-wise French intensive method of gardening. If you are planting a new landscape, consider California native plants, which tend to be drought resistant.
Snails and slugs are just beginning to appear so watch for their damage. You can purchase commercial products to control them or try some more homespun methods. One tactic is to lay a board down where you see damage. Snails and slugs like to crawl underneath, so the next day you can stand on the board and crush them. You can also pick them off by hand if you go out at night with a flashlight.
Snails and slugs are hermaphrodites, which means they all lay eggs. They lay about 80 eggs four times a year, so it's important to keep them under control.
If you have plants in pots, now it the time to repot them. Use fresh soil and trim the old roots to make room for new ones. Try to match the potting soil to the needs of the plants. Most container plants need soil that drains well.
It's also a good time to move any plant that's in the wrong place in your garden. To make sure the top and the root ball are in proportion, trim both back when you transplant.
Start seeds for summer vegetables and other plants in February and March. I use a commercial seedling mix for this process. It is especially designed for newly emerging plants.
Be sure to read the seed packets for sowing instructions. Some seeds take longer to sprout than others and some need to be planted deeper than others. Keep your newly planted seeds by a sunny window. If you have a heat lamp or a seed-heating pad, they will appreciate that special treatment and sprout more quickly. Keep the soil damp but not soggy to prevent seeds from rotting before they sprout. You can also make a mini hothouse by inverting a large bottle over your seedling pot.
If the dry weather continues, monitor your in-ground plants and container plants. If the soil is dry, it's time to water. I have noted that some of my pots have dried out even though it has been cool this winter. Also, if we have a hard freeze, plants will survive better if they have moisture. I know this from experience.
Food Growing Forum: Napa County Master Gardeners will host this forum on “Planning & Record Keeping and Crop Rotation” on Sunday, February 13, from 3 pm to 4 pm. Register to receive the Zoom link at https://ucanr.edu/2022FoodForumFeb.
Workshop: Napa County Master Gardeners will hold a workshop on “Weed ID, Frost Protection and Drip Irrigation” on Saturday, February 26, from 11 a.m. to 1 p.m., at Las Flores Learning Garden, 4300 Linda Vista Avenue, Napa. Register: https://bit.ly/3J1QFl8
Workshop: Napa County Master Gardeners will hold a workhop on “How to Improve Home Vineyard Soil Health for Grape Quality and Climate Change” on Saturday, February 26, from 9 a.m. to 12:30 p.m. Whether the workshop will be in person or via Zoom is still being determined.
You must register to attend. Registrants will receive an email a few days before the event with the workshop location or Zoom link. Register at https://ucanr.edu/2022HomeVineyardSoilFeb
Workshop: Napa County Master Gardeners will hold a workhop on “Your Soil Can Save Us! Garden Soil and Climate Change” on Sunday, February 27, from 1 pm to 3 pm, at Yountville Community Center, 6516 Washington Street, Yountville. Details: https://napamg.ucanr.edu
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit https://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Susanne von Rosenberg, UC Master Gardener of Napa County
One of the reasons I really enjoy having fruit trees is that they are perennials: they give back a lot for relatively little effort. You can get the same benefits from perennial vegetables.
The most common perennial vegetables for our area are artichokes, asparagus and bunching onions (scallions). Others that are highly suited to our Napa Valley climate are cardoon (a relative of artichokes), tree collards (also known as tree kale or walking stick kale), walking onions (also called Egyptian onions) and nopales (prickly pear cactus pads). Additional options include sunchokes (Jerusalem artichokes), perennial arugula (caution: it self-seeds readily) and miner's lettuce (claytonia). In our climate, miner's lettuce acts like a self-seeding annual, but it is a perennial in areas where it receives sufficient moisture.
In addition, you can “perennialize” regular kale, garlic (for green garlic) and, to some degree, Swiss chard and broccoli. To start treating regular kale as a perennial, simply cut it back to a few inches of stalk when it starts to look tired and it will resprout. You can do the same with broccoli. You won't get another large head, but you will refresh the plant and get more small side shoots.
In my yard, Swiss chard readily self-seeds, so there is always some chard growing wherever I water regularly. If it's not in the way, I let it grow. If you plant garlic and don't harvest the bulb, it will sprout as a cluster of green garlic the following growing season and continue to create bulbs underground. Eventually, as with flower bulbs, you will have to dig it up and divide it. Keep some of the best bulbs and replant some cloves for more green garlic.
Think about the pros and cons when you consider adding perennial vegetables to your garden. The main advantage is that you only plant once, yet you harvest for multiple years. Because the plants stay in place longer, they develop stronger and more extensive root systems. This helps the plants take better advantage of available water and nutrients.
Because you're not replanting every year, you're protecting the soil ecosystem. For busy people, adding one or two perennial vegetables per year can be a way of building a productive vegetable garden without investing a lot of time.
You can also let the plants flower, which supports pollinator insects. Some perennials add beauty to your garden. Sunchokes, which are part of the sunflower family, will grow 8 to 10 feet tall with adequate water and produce numerous small sunflower-like flowers.
However, there are some downsides. First of all, you lose flexibility. You have to carefully consider how big the plants will get and whether they make sense at full size in their proposed location. Good locations for perennial vegetables include areas adjacent to other perennials (including berries, fruit trees and ornamental plantings), at the ends of annual vegetable beds and in groupings with other perennials that have similar water needs.
For many perennial vegetables, it takes longer to get harvestable produce. Also, you may need to keep watering them when the weather is dry. When we have a light rainy season, you'll likely have to keep irrigating.
If you are not rotating vegetables and you are keeping them alive year-round, you may have more pest problems. Control pests as soon as you notice them. If you have gophers, you may find that certain perennial plants, such as artichokes, need to be planted in cages because the roots are just too tasty for gophers to resist.
Finally, because you are continuing to water, you are also likely to continue to get weeds, so you will need to cultivate around the plants or mulch regularly to keep the weeds down. Also make sure to check that you are selecting the right kinds of perennial vegetables for your garden. Many common perennial vegetables, such as watercress, require relatively high amounts of water or need sandy, well-drained soil. Others can become invasive. Do your research or contact the Master Gardener help desk for more information.
There are many other perennial vegetables to try if you're adventurous. On the border between herbs and vegetables are sorrel and lovage, which can be used as salad greens, in soups and as seasonings. Daylily tubers, young shoots, buds and flowers are all edible. The leaves of scorzonera (black salsify) can be harvested and eaten just like lettuce. (If you harvest the edible roots, however, you will kill the plant.) Sweet potato leaves are also edible, as are linden tree leaves. Have fun diversifying your garden!
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, February 4: Soil is the Solution: Healing the Earth One Yard at a Time.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Susanne von Rosenberg, UC Master Gardener of Napa County
Weeds can serve some useful purposes, but unless you're an unusual gardener, you probably still prefer to decide what gets to grow in your garden and what doesn't. The four basic weed control methods are prevention, removal, smothering and exhaustion. Most gardeners will need a combination of these methods to control their weeds.
Annual weeds (those that sprout from seed each year) are easier to control than perennial weeds (those that regrow each year from underground structures such as roots, tubers and underground stems). Perennial weeds can spread from their underground structures and by seed.
Prevention consists of all the activities that keep weeds from growing or spreading. The most important one by far is preventing weeds from setting seed. Some plants, such as wild oats, produce “only” about 250 seeds per plant. More ambitious weeds can produce over 200,000 seeds per plant.
It's also important to avoid promoting weed growth. Soil scientists estimate that there are 140 weed seeds per pound of surface soil in cropland (or 200 million per acre). Most weed seeds sprout from the top half-inch of soil. If you can avoid disturbing the soil, you can minimize the weed seeds you bring to the surface for germination.
Controlling drip irrigation is another weed prevention method. Only put water where you want plants to grow.
Mulch is effective in controlling annual weeds as long as it's thick enough. Mulches prevent light from reaching the weed seeds, so weeds can't grow. I prefer mulches from natural materials, such as wood chips and compost. Coarse mulches need to be three to six inches thick to keep out the light, and finer mulches such as sawdust and grass clippings need to be one to three inches thick.
Make sure that water can still reach your plants; mulches absorb some of the water. Certain quick-growing vegetable plants, such as squashes, beans and tomatoes, form a thick leaf cover that also helps to shade out weeds.
If you feel ambitious, you can kill many weed seeds through soil solarization. This process will take four to six during the hottest part of the year, so you will not be able to grow a summer garden in that area. To be effective, it needs to be done correctly. The UC Integrated Pest Management Program website has detailed information.
To avoid spreading weeds between different areas of your garden or between your garden and someone else's, clean your garden equipment, clothing and shoes. Finally, avoid importing seeds. While manure is great for your garden, make sure it's composted first. Horses and cattle can pass 20 percent of the viable seeds they eat. Composting can kill many of those seeds, but bird manure is usually a better choice.
As for removal, one effective approach is “water, wait, cultivate.” Ready your planting bed several weeks before you intend to plant, and then water it to encourage weed seeds to sprout. Hoe out the sprouts, keeping your hoe shallow to cut off the weeds just below the surface. Then repeat this process. This approach will remove about 95 percent of the weeds that would normally sprout. When you plant, disturb the soil as little as possible to avoid bringing new weed seeds to the surface. Keep hoeing or removing weeds by hand throughout the growing season. If you've applied mulch, it's usually easy to remove the relatively few weeds that sprout by hand.
Smothering weeds is simply another form of mulching known as sheet mulching. Cut back your weeds to six inches or less and cover the area with cardboard, overlapping the sheets by at least six inches. Apply mulch on top of the cardboard. The cardboard will break down in three to four months if you keep it moist, and it prevents annual weeds from returning.
Sheet mulching will also temporarily banish perennial weeds, but they may re-emerge after the cardboard has broken down. For me, sheet mulching is the fastest and easiest way to reclaim weedy areas.
To get rid of perennial weeds that are already established in your garden, you need to exhaust their food supply stored in their roots or other underground structures. Let them grow a bit, cut them back to below the ground surface, then let them grow a bit again. Don't let them grow a lot because that could allow them to store more food. This process may take several years to work. If you have widespread perennial weeds (for example, Bermuda grass), you can repeatedly mow them close to the ground.
You might have noticed that I did not mention herbicides. They are truly a last resort and are usually not needed in home gardens. If you are growing your ornamentals, food plants and turf correctly, they will outperform most weeds. If you do have to use herbicides, follow the label directions carefully and use the least amount possible. However you tackle your weeds, just remember: they may be tough, but you're a lot smarter.
UC IPM has more information about weeds for Napa county home gardeners. Start here:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7441.html
The UC Master Gardeners of Napa County are volunteers who provide University of California research-based information on home gardening. To find out more about home gardening or upcoming programs, visit the Master Gardener website (napamg.ucanr.edu). Our office is temporarily closed but we are answering questions remotely and by email. Send your gardening questions to mastergardeners@countyofnapa.org or leave a phone message at 707-253-4143 and a Master Gardener will respond shortly.
By Susanne von Rosenberg, UC Master Gardener of Napa County
It's May and everything is growing beautifully, including weeds. Even if your garden is exceptionally well-weeded, new invaders will creep in and demand attention. Our general reaction is to remove them as soon as we realize that we have them, and we think of a good, tidy garden as one that is free of weeds.
In general, until you are comfortable with weed identification, keeping your garden entirely free of things that you did not plant is a good approach. However, weeds can also provide some benefits, so learning about the different weeds can help you decide whether you just might let certain ones grow for a while. Over time, you may make friends with certain weeds and make them part of the cycle of your garden.
So what is a weed? Most commonly we consider something a weed if it is growing somewhere we don't want it to. Those California poppies you love in your flower beds just might be a weed if they start growing in your vegetable bed. I was surprised to learn that some people consider miner's lettuce, an edible California native that I carefully cultivated in my garden, a weed.
How can weeds actually be beneficial? Some weeds are edible, many can supplement your compost, and some help loosen the soil. They may provide erosion control and dust control. Some provide food or habitat for pollinators and other wild animals.
In addition, weeds can teach us about our soil. Certain weeds prefer specific soil conditions, so if you have those weeds, you can assume that your soil has those characteristics.
Common edible weeds include purslane, dandelion, lamb's quarters, nettles, fennel and chickweed. If you're not sure what you're looking at (you only know it's not something you planted), you can use the weed identification tutorials and information on the University of California Integrated Pest Management (UC IPM) site. If you're going to eat weeds (the ultimate revenge), use common sense. Never eat anything if you're not totally certain you've identified it correctly.
Many weeds make good additions to your compost or can serve as mulch. Annual weeds that have not developed flowers can be chopped up and left in place, although in winter and in moist areas of your garden, you have to make sure they don't re-root. You can also chop them and add them to your compost bin.
Those parts of perennial weeds that won't re-sprout can also be added to compost or used as mulch. With perennial weeds, though, it's important to know how they propagate so you don't inadvertently spread a problem. If a perennial weed has not flowered, you can also let it dry out completely (think completely crispy and brown) and then put it into your compost.
Some weeds improve soil by growing deep roots that break up the subsoil (the layer immediately below the topsoil). That allows the weaker roots of more delicate plants to access the water and nutrients there. Some common weeds with deep, strong roots include wild chicory, plantain, sow thistle and vetch, as well as lamb's quarter and purslane. Cut these weeds off at the soil surface before they start to flower. The roots will decay in place, adding organic matter to your soil. The tops can go into your compost. You'll get the most benefit if you keep these weeds fairly far apart; if they grow close together their roots won't penetrate as deeply.
Some weeds are great for attracting pollinators. However, you have to let the weeds flower. The mustard we see flowering in Napa Valley vineyards is one example. Fennel, wild radish and pigweed are other examples of weeds that are good pollinator plants. Pull them as soon as they have bloomed, and do not put the spent flowers in your compost.
Weeds can also act as living mulch. This feature can be particularly helpful in winter, if you are not growing vegetables or an intentional crop such as fava beans. Almost any annual weed can serve as living mulch. (You do not want to give perennial weeds the benefit of extra growing time.) Some annual weeds, such as chickweed and purslane, will form a mat as they grow and thus help suppress other weeds.
Finally, weeds give you clues about what is going on with your soil. Like other plants, weeds have specific soil preferences. Chicory, purslane and lamb's quarters are generally good news because they indicate rich soils. Thistles, wild turnip and bindweed, on the other hand, can indicate that you have compacted soil or a crusted soil surface. Poor drainage can be indicated by weeds such as sedges and Bermuda grass.
Research your weeds and learn what they tell you about your garden. Whether as indicators, food or soil improvers, weeds can be garden helpers, too.
Weed photo gallery list from UC IPM is here, a LIST OF ALL WEEDS. Find the common name to see a photo.
http://ipm.ucanr.edu/PMG/weeds_all.html
If you wish to ID the weed, use the UC IPM weed ID tool here:
http://ipm.ucanr.edu/PMG/weeds_intro.html
The UC Master Gardeners of Napa County are volunteers who provide University of California research-based information on home gardening. To find out more about home gardening or upcoming programs, visit the Master Gardener website (napamg.ucanr.edu). Our office is temporarily closed but we are answering questions remotely and by email. Send your gardening questions to mastergardeners@countyofnapa.org or leave a phone message at 707-253-4143 and a Master Gardener will respond shortly.
By Rob Williams, U. C. Master Gardener of Napa County
With this season's deluge of wet weather, thoughts of a bountiful summer harvest might seem far away. However, the emergence of some buds in trees and slightly higher day and night temperatures serve as a gentle reminder that spring is imminent.
With this in mind, there are a few things you can do right now to help ensure a successful summer vegetable harvest. Good preparation, thoughtful cultivar selection and consideration for the overall ecology and health of your garden are the foundations of a productive outcome.
Draw up a simple garden plan to help organize your activities. Decide what you will plant and when so you can maximize space, rotate crops and insure your crops have enough time to complete their growth cycle before the next season.
Radishes, for example, grow quickly whereas autumn squash might need several warm months. A plan can also guide you in timely ordering of seeds and seed starting.
Consider, too, such things as construction or repair of raised beds and irrigation lines. Are your irrigation lines still viable after a season of limited or no use? Repairing or replacing them over the next few weeks can help insure your garden is in shape for summer.
Get weeds out now while they are easy to pull. Consider planting a cool-season cover crop such as fava beans or peas. These quick-growing legumes can displace weeds, add nitrogen to the soil and serve as a component in your crop-rotation scheme. As a bonus, they are edible. After you harvest the pods, chop the greens and use them as mulch to improve soil tilth. Their extensive root systems can help break up compacted or heavy soils so you don't have to till wet soil, which is definitely not a good idea.
What to plant? With Napa Valley's Mediterranean climate, many summer vegetables feel right at home in pretty much any part of the county. Tomatoes, peppers, squash and corn are favorites in many local gardens. Of course, you should take into account your particular microclimate—any shady or windy areas, for example.
Local nurseries have a good selection of vegetable seeds and starts, but also consult specialty catalogs for heirloom vegetables and new hybrids that look enticing. Many heirlooms have exceptional disease resistance, flavor and overall hardiness. What's more, you can save their seeds for next year's crop, thus reducing your gardening expenses and increasing the diversity of your harvest. Hybrids have to be started from new seed every year.
Finally, consider the overall ecology of your garden. What can you do to improve it? Adding compost now can help prepare the soil for your transplants. Earthworms and other soil microorganisms will get started on making your soil a better host for the upcoming guests.
And while your main focus might be vegetables, consider planting other plants as pollinators. Nasturtiums can add color to your garden and serve as a resource for pollinators. And their edible blossoms can add a peppery note to salads. Blooming herbs and sunflowers also attract pollinators, which will increase the bounty of your harvest. Birds appreciate these plantings, too, and help keep pest populations down so you don't have to resort to harmful pesticides.
We avid gardeners look forward to a bountiful summer harvest. With a bit of planning now, we increase our chances of success.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Growing Summer Vegetables” on Saturday, March 11, from 9 a.m. to 11 a.m., at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Learn what the garden needs to successfully produce spring and summer vegetables from seeds and seedlings. The workshop will cover soil types and preparation, temperature essentials, watering, fertilizing and harvesting, with a dash of integrated pest management. Online registration (credit card only); Mail-in registration (check only or drop off cash payment).
Garden Forum: Join the U. C. Master Gardeners of Napa County at a forum for home gardeners on Sunday, March 12, from 11 am to 1 pm at Yountville Community Center, 6516 Washington Street, Yountville. Bring anyquestions about anything in the home garden. Questions about fertilizing, watering, planting, plant care, diseases and pests, tools and tool care or nursery purchases are welcome. Register with Yountville Parks & Recreation or contact 707-944-8712.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.