The chemistry behind oxalic acid
As an acid, oxalic acid is corrosive. It is used as an industrial bleaching agent and heavy-duty cleaning product. Apparently, it works especially well on removing rust. Oxalic acid is also classified as nephrotoxin, which means it can damage your kidneys. Oxalic acid, in the form of calcium oxalate, is the most common ingredient of kidney and urinary tract stones. Oxalic acid can also cause joint pain. At high concentrations, oxalic acid really is deadly. According to the National Institutes of Health, lethal doses range from 15 to 30 mg, though an oral dose of 5 mg has been fatal.
In each of these cases, it is the amount of oxalic acid being ingested that is the problem. The levels found in many foods are too low to cause problems. Bottom line, a 150-pound person would need to eat approximately 12 pounds of rhubarb leaves for it to be dangerous. And spinach leaves contain more oxalic acid than rhubarb leaves. That's why your teeth may feel funny after eating spinach. It's oxalic acid crystals binding with any nearby calcium to create calcium oxalate crystals. These crystals stick to your teeth for several minutes to an hour.
Oxalic acid in nature
Oxalic acid is found in a surprising number of food plants that we eat every day. The trick is in the concentration. In fact, oxalates can be toxic to plants, too, but plants bind those oxalates up in crystals that they then use as tiny spears to defend themselves against herbivores. These specialized cells are called idioblasts. Oxalic acid is formed when plants burn sugars and carbohydrates as fuel.
Oxalates are also used to balance calcium levels, within the plant, by binding to calcium molecules. This is why some people say eating high levels of oxalic acid can interfere with healthy bones and teeth, but, again, you would have to eat an awful lot—over a long period of time—to cause any real problems. By the way, our bodies produce oxalic acid out of Vitamin C, on purpose. Also, cooking plants that contain oxalic acid has not been shown to reduce oxalate levels.
Armed with this information, I went out to my rhubarb plant and broke off a young leaf and ate it. The flavor was actually pretty nice, something akin to spinach, but lighter. And I lived to tell about it.
by UC Master Gardener Kate Russell
Photo: South Valley Magazine
This article first appeared in the January 5, 2018 issue of the South Valley Magazine.
Chicory is commonly used as a coffee substitute
Chicory is a woody perennial that comes in many different varieties, depending on the cultivar used: roots (var. sativum) and leaves (var. foliosum) are the most common. Chicory, occurring naturally, can indicate compacted soil. Luckily, its deep taproot help breaks up that compacted soil, plus it's drought tolerant!
Chicory as food
Chicory is a highly versatile plant. Its slightly bitter leaves are used in salads, the buds can be blanched, and the taproots are frequently roasted and ground up as a coffee substitute. You can reduce the bitterness by changing the cooking water two or three times. Roots are harvested before flowering stems emerge. These roots can be cooked and eaten the same as carrots or parsnips, ground into flour for bread, or used as a coffee substitute. Plus, chicory contains twice as much of the cancer-fighting, heart-healthy polyphenols found in spinach.
A member of the daisy family (Asteraceae), chicory (Cichorium intybus) is one of those large, gregarious groups that may surprise you. For example, curly endive, Belgian endive, and radicchio are all types of chicory. Lettuce and dandelions are close cousins, while chicory's distant cousins include sunflowers, artichokes, and yarrow. Also known as cornflower, bachelor's buttons, coffeeweed, blue daisy, and wild endive, chicory's flowers are composite, and leaves are normally toothed or lobed. Plants grow 10 to 40 inches tall. Flowers appear July through October.
How to grow chicory
In our planting zone (9b), chicory is a cool season crop that can be started in January and February for an early summer crop, and again in July or August for an early winter crop. This gives the seeds time to get started before the weather turns too hot or too cold. Summer's heat causes chicory to bolt, but a light frost actually adds just a touch of sweetness. Seeds should be planted 1/4 inch deep and thinned to 12 inches apart. Avoid overhead watering, as the leaves are prone to rotting.
Chicory pests and diseases
Despite its rugged nature, there are some pests and diseases that can impact chicory. Bacterial soft rot, damping off disease, fusarium wilt, white mold, anthracnose, and downy mildews are all diseases that attack chicory. Aphids, cabbage loopers, beetles, leaf miners, thrips, and slugs and snails may feed on your chicory plants.
Chicory grows like a weed. Once established, you can pretty much ignore it until you decide to harvest whatever part you have a hankering for. And, hey, even the flowers are edible!
by UC Master Gardener Kate Russell
Photo: South Valley Magazine
This article first appeared in the December 17, 2017 issue of South Valley Magazine./h3>
Top five methods to preserve your harvest
You can make the most of your garden harvest by keeping everything fresh and harvesting fruits and vegetables as soon as they are ready. Leaving them on the vine or stem for too long and they can attract pests and diseases. Flavor and texture also tend to deteriorate over time.
Fruits can be simmered and pureed and then either canned or frozen. It can also be dried into fruit leather. Vegetables can be cooked, pureed, and then frozen for later use in soups, casseroles, and other recipes. All those zucchini can be cooked into Chocolate Zucchini Cake for a popular dessert that always disappears quickly. They can also be stuffed and frozen for a simple pop-in-the-oven dinner.
Freshly picked and washed produce can be placed in a resealable plastic bag or container and stored in the freezer. If you have an abundance of tomatoes that you will be canning, this is an excellent way to retain that fresh flavor while waiting for enough ripe fruit to warrant firing up the stove. Peas and beans should be hulled before freezing, but those pods can be tossed into a separate freezer bag to be used to make soup stock come winter.
Canning tomatoes is an easy way to store food from your garden. The acidity in tomatoes makes them far less likely to develop mold. That being said, enlist the help of an experienced canner and be sure to follow food safety guidelines whenever canning.
Many fruits and vegetables from your garden can be dried for future use and easy storage. Grapes, peas, and beans can be dried at room temperature. For other foods, you can use a commercial dehydrator or your oven. Times and temperatures vary, depending on the type of food and its thickness. You can look online or go to your local library for specific instructions.
Sometimes, your garden will simply produce more food than you can use. Family, friends, and neighbors should always top the list when your garden produces abundance. Local food banks and other charities are nearly always happy to accept donations of fresh fruits and vegetables.
Rather than tossing out the fruits of your labor, make the most of your harvest with these simple methods for prolonging your garden's shelf life.
by UC Master Gardener Kate Russell
Photo: UC, Melissa Womack
This article first appeared in the August 17, 2017 issue of South Valley Magazine.
Choose your own ‘native garden' adventure
But even after all this rain, don't think for a minute that I'm going to start taking a bath every day. Oh, I didn't mean that either. What I do mean is that even after all this rain, the water that we, and our plants, drink, is still a scarce resource. And there are no better plants for sipping that precious water slowly than some of our own California native bulbs, bushes and trees. From formal gardens to cottage gardens, children's gardens to edible gardens, you can—and should—choose your own (native garden) adventure this spring.
I planted my first California native garden in my front yard more than eight years ago, and recently I've been thinking that it's about time for a makeover. And for this new adventure, I've decided on a pollinator garden to attract native birds, bees and butterflies. Want to give it a try, too? Here's how to get started:
Choose a spot in full sun that is weed-free, with soil that is moderately well draining. No need to redo your entire yard at once. It's OK to start with one small area.
Consider adding a natural arrangement of attractive boulders and rocks.
If you are handy enough to install one yourself, or able to pay a professional, include a basic drip irrigation system (before planting.) Otherwise, give your plants a deep soak when you plant them, with additional monthly deep soaks. Watch for heat waves in the forecast, giving them additional water a few days before any hot weather event.
Plant some of the following pollinator favorites, which will provide colorful blooms and foraging habitat throughout the year:
Wildflowers: Baby blue eyes (Nemophila menziesii), Globe gilia (gilia capitata), California poppy (Eschscholzia californica)
Shrubs and subshrubs: Foothill penstemon (penstemon heterophyllus), Gumplant (grindelia spp.), California aster (symphyotrichum spp.), California lilac (ceanothus), Oregon grape (berberis aquifolium), Silver bush lupine (lupinus albifrons), California buckwheat (eriogonum fasciculatum), and yarrow (achillea millefolium)
Once your plants are in the ground, remember to keep the weeds to a minimum or they will compete for your California natives' resources. Avoid using pesticides and choose hand weeding instead, which is a built-in opportunity to check soil moisture levels and identify pests and disease in their earliest stages. For more information about creating a pollinator garden, check out the Xerces Society's “Bring Back the Pollinators” campaign.
by UC Master Gardener Cayce Hill
Photo: courtesy of Master Gardener Allen Buchinski
This article first appeared in the April issue of the South Valley Magazine./h3>