Mycorrhizal fungi develop mutually beneficial symbiotic relationships with plant roots. Photo by Edward L. Barnard, Florida Department of Agriculture and Consumer Services, Bugwood.org.
If you have taken an elementary school science class, you have probably learned the basics of photosynthesis. In case you are a bit rusty, photosynthesis is the process by which plants capture sunlight to manufacture their food. They absorb carbon dioxide from the atmosphere and water from the soil. With these ingredients, they create carbohydrates, or sugars, that supply the energy to grow and develop.
As you can imagine, this energy is vital to the health of the plant. But fascinatingly, plants expel between 20 and 40 percent of these sugars from their roots into the surrounding area around the roots. The sugars that the plant releases, along with amino acids, organic acids, enzymes, and other substances, are called root exudates. The area just inside the root where the sugars are released, and the area just outside the root where the sugars end up, is called the rhizosphere.
But why would a plant waste this energy? This is because they derive benefits from the unique microbial population that inhabits the rhizosphere. Plant roots are limited by the amount of nutrients they can take up in the soil. By feeding microorganisms their sugars, they are essentially recruiting workers to help them scavenge for nutrients in areas that they cannot access on their own.
A microscopic image of mycorrhizal fungi in black walnut. Photo by Robert L. Anderson, USDA Forest Service, Bugwood.org.
Bacterial colonies, which are types of microorganisms, establish themselves within the rhizosphere and feed on the root exudates, allowing the bacteria to multiply. Along with the sugars they take in from the root exudates, they also take in nutrients from the soil. The waste that is produced by the bacteria is rich in bioavailable plant nutrients, which the plant then uses, creating a plant-microbe symbiotic relationship where everyone wins.
Another type of specialized microorganism, mycorrhizal fungi, also develops a symbiotic relationship with plants. Its meaning is within its name, as “myco” literally means fungus and “rhiza” literally means root. There are an estimated 50,000 fungal species that form these beneficial relationships with approximately 95 percent of plant families.
The mycorrhizal fungal hyphae, which are tiny fungal filaments one cell thick, do not have chlorophyll and are therefore not able to photosynthesize. Instead, the fungal networks have a large surface area that allows them to be particularly good at extracting nutrients from the soil. This enables them to access nutrients that plant roots would not be able to access on their own. The fungi drill into the plant root and trade these nutrients, along with water, with the plant in exchange for the sugary root exudates. In this way, both the fungi and the plant benefit from the relationship. Interestingly, these types of relationships will only develop once the plant releases particular root exudates that attract the microorganisms they are seeking. In essence, the mycorrhizal fungal hyphae will not associate with the root until they are invited.
Along with root exudates, root hairs and other plant cells accumulate within the rhizosphere as they grow and die throughout the plant’s life cycle. The combination of the root exudates, dead root hairs, and dead plant cells creates essentially a compost pile within the rhizosphere. This combination of substances establishes an environment where beneficial microorganisms can thrive, and a plant can maximize its nutrient uptake capacity.
Amazingly, there can be up to a billion bacteria and several yards of fungal hyphae living in just one teaspoon of soil! Of course, not all microorganisms are beneficial to the plant. But remarkably, plants have developed many ways in which they benefit, and ultimately thrive, in this diverse soil ecosystem.
As humans, we continue to learn more and more about these complicated and interesting interactions taking place in the soil beneath us. And the more we learn, the more we discover just how important these diverse ecosystems are to the health of the food web, and therefore, to the health of our planet as a whole.
Butternut squash is more resistant to squash vine borers and it has a vining growth habit, perfect for growing on a trellis. Photo by Janis Piotrowski.
Last spring, I fought the good fight against a very pesky garden pest. As the pandemic ramped up, I started working remotely from home, which I figured would at least afford me the ability to scout my patch of summer squash a bit more diligently.
I was able to successfully remove a few tiny eggs that had been deposited individually on the base of the squash’s elongating bright green stems. And, since I planted early in the season, I was able to harvest a few beautiful looking – and very delicious tasting – summer squash for the dinner table. But alas, most of my hard work succumbed to my biggest garden foe: Melittia cucurbitae. Aka, the squash vine borer.
Squash vine borer larvae can most easily navigate the stems of summer squash varieties. Photo by Molly Jameson.
This year, I am trying a new approach. Instead of marching through my garden morning and night swatting wildly at borer moths – or repeatedly coating Baccillus thuringiensis biological insecticide spray over the squash stems every week – I am switching it up. This year, it is all about Cucurbita moschata. Aka, butternut squash.
How can this cucurbit avoid the mighty squash vine borer, you ask? Well typically, after hatching, squash vine borer larvae will quickly chew into the succulent stem of a summer squash variety. These large, hollow stems then act as an open highway for the borers, and they easily work their way up. The stems of butternut squash, on the other hand, are less palatable for the larvae. Their vining habit produces stems that are harder to navigate, thicker, and tougher than summer squash stems. Although not completely resistant, they are certainly not the borers’ preferred host plant.
And thankfully, butternut squash is quite delicious. It can be roasted to accompany just about anything, including spaghetti, lasagna, salads, chilis, and stews. It can also be blended into soups or purees to be paired with herbs and spices, such as turmeric, sage, garlic, and thyme. Or, it can be used as a filling in pies or frittatas, brushed with brown butter to sweeten up the plate as a delicious side dish, or be paired with goat cheese and crackers to be served as an appetizer.
Sometimes, simply omitting your toughest garden foe’s favorite host plant is the best path to both garden and dinner plate success.
Sugar snap peas prefer to be planted when the soil is cool and the pods are delicious raw or cooked. Photo by Full Earth Farm.
Leon County’s Spring 2021 Seed Library Program Starts February 13
Although we are still experiencing the coolness of winter, the spring gardening season is right around the corner. To get a head start on the heat that will start taking over by May – and certainly by June – it is important to have a spring garden plan. If you want to start your veggies from seed, certain crops, such as tomatoes, need to be seeded soon for best results. Other warm-loving crops, like squash and cucumbers, also benefit from an early start to beat the life cycles of many common pests.
Need seeds to start your garden? Well, if you live in Leon County, you are in luck. Starting on February 13, 2021, residents of Leon County can “check out” up to three sample seed packets per month with their library card as part of Leon County’s Seed Library Program. The vegetable seeds can be checked out from any of the seven library branch locations. Leon County residents can apply for a library card online at the LeRoy Collins Leon County Public Library online card application page (https://lcpl.ent.sirsi.net/custom/web/registration/).
A young volunteer helped pack seeds from home for the Spring 2021 Leon County Seed Library Program. Photo by Jeanne Breland.
Here are the vegetable seed varieties that will be available starting February 13:
Italian Large Leaf Basil. This is a fast-growing plant, with four-inch-long green leaves that have an anise flavor and a sweet aroma.
Jackson Wonder Butterbeans. A high yielding heirloom, these beans produce pods with three to five reddish colored beans in each. When dried, the beans develop a mottled pattern.
A & C Pickling Cucumber. Plants are productive, producing many straight, dark-green fruits that are great for pickling when they are four to six inches long. Eaten fresh, they can be grown out to 10 inches.
Edisto 47 Melon. Plants prosper in hot, humid climates and produce mildly sweet five-pound cantaloupes in about 90 days.
Burmese Okra. Plants have very large leaves and at about 18-inches tall, produce slender curved 9 to 12 inch okra pods that are virtually spineless. Under 10 inches, pods can be eaten raw and are less viscous than some other varieties.
Sugar Snap Peas. Plants produce sweet, crisp pods that can be eaten raw or cooked. Seeds germinate well in cool soil and plant growth is vigorous, requiring support.
Corno di Toro Sweet Bell Pepper. This productive pepper, whose name translates to “Horn of the Bull,” produces thick horn-shaped fruit that is flavorful and great eaten raw or cooked.
Butternut Waltham Squash. This winter squash produces four-to-five-pound fruits with necks that are thick, straight, and cylindrical. The flesh of the fruit is smooth and has a flavor that sweetens with storage.
Black Krim Tomato. This Russian heirloom has indeterminate growth and produces 8 to16 ounce, brown-to-red fruit with a deep smoky flavor. The shoulders of the tomatoes are brownish green and darken with more heat and sunlight.
Matt’s Wild Cherry Tomato. This deep-red small cherry tomato has indeterminate growth and produces soft fruit that is very sweet and full of flavor.
Whether you are located in Leon County or not, everyone is welcome to join us Saturday, February 13, from 10:00 a.m. to 12:00 p.m., for our Leon County Seed Library Virtual Workshop. Via Zoom, agents with UF/IFAS Extension Leon County will discuss spring vegetable gardening techniques and food waste prevention. There will also be a live cooking demonstration showing how to prepare healthy meals and snacks at home, featuring vegetables available in the Spring 2021 Seed Library Program.
For more information about the Leon County Seed Library Virtual Workshop, please visit our Eventbrite page: https://spring2021leoncountyseedlibrary.eventbrite.com. There is no cost to attend the workshop, but registration is required.
Tatsoi is a low-growing green with spoon-shaped, dark-green leaves. Photo by Molly Jameson.
Sweet to the palate, easy to grow, and a delight to watch take shape, tatsoi is a great choice for your fall and winter veggie garden.
Tatsoi is in the cabbage family, species Brassica rapa, and is closely related to another Asian green, bok choy. It originates in Japan, where it has been grown for over 1,500 years.
Tatsoi is an annual with spoon-like dark-green leaves and cream-colored stems that grows low to the ground. It is easy to start from seed, can handle partial shade, and grows relatively fast. It can be eaten raw, like spinach, or it can be lightly cooked to add a pleasantly distinct flavor to stir-fries and soups. It has a surprisingly mild mustard-like taste. It is full of vitamin C, calcium, potassium, folate, and phytonutrients.
Tatsoi takes about 40 to 50 days to reach maturity. Photo by Molly Jameson.
Although it does well in the spring in cooler climates, it does best in fall and winter in Florida and can handle temperatures down to 15°F. It can be directly seeded into the garden and germinates in about five to 15 days. You can seed tatsoi one to three inches apart, but it should be thinned to about eight to 10 inches to reach full size, which takes about 40 to 50 days. Add the baby tatsoi you thin to your dinner salad.
Once thinned, harvest whole mature plants or individual outer leaves. If you find you just can’t get enough, seed more tatsoi every two weeks until the spring, when longer days and warmer temperatures will cause tatsoi to bolt. Bolting is when a plant diverts its resources away from the edible leaves and into the flowering stem for seed production.
For a truly continuous supply, allow your tatsoi to bolt, and it will produce many tiny, thin seed pods. Wait for the plant to dry completely and harvest the seed pods. Carefully open the pods over a plate to be sure to catch all the small round seeds within. Then, simply store the seeds in a dry, cool location, such as your fridge, in an air-tight container. Stored correctly, the seeds will last four to five years.
If you have yet to give tatsoi a position in your garden, give it a try this winter!
