Facts vs Myths on the latest garden trends
Guest Contributor: Cassey Anderson, CSU Horticulture Agent
Should you plant a cover crop this winter? What's hugelkultur about? Need help sorting through the latest trends in home gardening? Here's a look at a few gardening facts vs myths, from hugelkultur to cover cropping. Some of these "hot" approaches have great scientific research behind them, some have good aspects, others may not live up to their hype. Let's take a look!
Lasagna gardening is a garden practice in which you layer “greens” and “browns” in lasagna-esque layers to provide a simple, no-till compost area. This is a great way to compost; it balances the two key components for compost (see our "Composting 101" article for details). However, although it’s a good system for creating compost, planting should not happen in the space until the composting process has been completed.
How long does Lasagna Gardening take? In some parts of America, or with the addition of a good amount of moisture for those of us who are in dry climates, this may not take very long, but left to its own devices it could take a season or longer. Patience is the name of the game for getting successful completed compost out of this process, but it can be a great way to start a new area. This system becomes complicated when combined into an active garden bed. Microbes that help break down the “browns” will consume available nitrogen to do so, which offsets the balance of Carbon and Nitrogen making plant growth challenging.
Sheet mulching with cardboard
Sheet mulching with cardboard is commonly touted as the best eco-friendly way to start a new garden area, smother weeds and as a general cure-all for problematic plants. When used appropriately it can work, but it’s not a long-term solution. Really, it’s best to mulch with 3-4” of mulch (wood chips, rock, straw or grass for veggie gardens etc.) with nothing underneath to allow for the best movement of air. If moisture is not present, the cardboard could potentially reduce gas exchange for plant roots. Unfortunately, there have not been very many studies on soil oxygen levels and sheet mulching, but if using this system be sure to keep an eye on your plants, if they start to look less than happy it may be time to pull some of the cardboard out.
Described as a centuries-old technique, the first references to hugelkultur actually begin in the 1960s. This garden technique creates a mound bed around a combination of large branches and twigs, grass sod, leaves, and compost in concentric layers. If you’ve read this far you may begin to see some similar issues as we have with the above two practices. Additionally, these systems require a substantial amount of moisture to ensure continued breakdown of the plant material. The carbon and nitrogen ratio may become problematic for plant growth. Anecdotally, I have not seen it be successful here in Colorado due to our dry climate. For a more in-depth look at hugelkultur see: https://pubs.extension.wsu.edu/hugelkultur-what-is-it-and-should-it-be-used-in-home-gardens
Now we get into a garden practice that I embrace whole heartedly, (provided you’re not afraid of a little labor). Cover crops are a great way to improve soil in a vegetable garden in the off season. Typically, they are sown at the end of the growing season, although some gardeners may allow a bed to remain fallow with a cover crop for a season. They can be comprised of many different things including mustard, daikon, winter wheat, annual ryegrass, clover, cowpea, winter pea, vetch, white clover. Cover crops can help increase moisture retention, soil organic matter, soil nutrients (if you use a nitrogen fixing legume crop), reduce erosion risk, they can even break up compacted soil layers.
When planning what cover crop you want to use be aware that if you plant a perennial you must have a plan to kill it, this will depend on the crop, and can be laborious or you can use chemical control. However, if you plant an annual you could use the dead plant material as a mulch and plant your new vegetable crops directly into it the next year, this can cut down on weed issues.
Crop rotation can be an asset to the home gardener. This is the practice of changing where you plant your vegetable families each season. For example, tomatoes, potatoes, peppers, eggplants and tomatillos are all solanaceous crops and should not be planted in the same area every year; it’s best to leave a year or more gap before planting in the same area again.
Rotating crops can help with soil nutrition. Planting corn in a bed the season after you’ve had peas or beans there could reduce your need to fertilize since both peas and beans are able to fix nitrogen from the are into a plant available form.
Crop rotation can be recommended at times for insect control, however its more effective for disease than insects since insect pests are mobile. If planting in containers you can simulate crop rotation by using new potting soil rather than re-using the soil year after year.
If you have more specific questions on any of these topics or need more specific assistance with your situation please contact your local county Extension office.