Preparing pots for planting at Camelot Gardens. Image, Karen Prather.
[SW Colorado | March 2020 | By Mary Menz]
Depending on which USDA hardiness zone you live in—and that ranges from 4a to 7a in SW Colorado’s various elevations—spring planting may come later rather than sooner. The last frost date is the date from which we determine and plan our spring gardening schedule.
Regardless of elevation, there are plenty of things to do before sowing seeds and transplanting vegetable or flower starts into patio containers and raised beds. When the daily temperatures in your area are consistently in the fifties or more, it’s time to start your preparation. The real pay dirt will come when it’s time to plant. You’ll be fully prepared to put your pots, raised beds, and garden plots to work.
Create a personal compost site or locate a public composting facility. If you’ve been dreaming of your own nutrient-rich soil amendment to add to your pots and garden beds, this is a good time to create one. Visit your local CSU Extension Office or search their website for its publication, “Composting Yard Waste–7.212,” for more information.
Pick up and remove leaves and twigs that settled into your pots and gardens over the winter. Add this “brown” debris, along with dried annuals and dead perennial foliage, to your compost site with nitrogen-rich “green” additives such as alfalfa meal and, of course, water to speed up the composting process.
“Soil health is the single most important aspect of gardening,” said Colorado Master Gardener Larry Wobeter. “Minimize its disturbance and leave cover crops and leaves on the garden for as long as possible before moving them to the compost pile.”
Wobeter stressed that beneficial insects overwinter in the garden debris and they shouldn’t be disturbed too soon. He also said that a very light tilling of winter cover crops is good to do at this time. “Radish is an especially good winter cover crop,” he said.
Loosen and aerate soil in garden beds and add about three inches of top dressing, such as compost or other amendments. The top dressing will add nutrients to the soil and help keep the soil moist. Wobeter said to wait three to four years before planting tomatoes, potatoes, or peppers in the same spot, because these plants deplete the soil of certain nutrients.
If most of your gardening is on the patio in containers, remove half of the existing soil and renew it with purchased amendments from a garden center. “It’s a good idea to refresh the growing medium in garden containers at least every year,” said Camelot Gardens greenhouse manager, Kayla Salonek. She recommended replacing at least half of the soil in each container to prevent insect or disease damage to new plants. Salonek also recommended that no fertilizers or preemergent weed control be applied to the pots or gardens until later in the growing season.
If you planted tomatoes in a pot last year, be sure to plant tomatoes in completely new soil to avoid soil-borne wilt diseases. The old soil can be used, if amended, for other types of plants as long as they’re not potatoes, tomatoes, or peppers.
Pull unwanted volunteers that sprout up before they have time to establish themselves. Whether they’re weeds or simply plants out of place, volunteers may or may not be welcome in specific garden spaces.
Determine the last frost date for your hardiness zone and work backwards to create your indoor seed-sowing schedule. Use heat mats and grow lights as needed to encourage healthy plant growth. The friendly staff at any nursery is knowledgeable and can outfit novice-to-expert seed-sowers with recommended seed-starting kits, growing mediums, and more.
Make a list of seeds or plants you look forward to growing this year, including species that will bring pollinators to the yard. Even a vegetable-only garden will profit from the colorful blooms of herbs and flowers that bring moths, butterflies, and other beneficial insects to the garden. Also, be sure to establish plant groupings according to sun and watering needs.