As a gardener, Spring on the Rocky Mountain Front Range can be a frustrating season. From sunny 70 degree days to frigid snow, from calm foggy mornings to gale force winds, we see it all, and sometimes all on the same day! Fortunately, if we choose the right plants, we can start gardening nice and early, in spite of the challenging weather. What follows is a brief synopsis of plants, seeds, roots, and bulbs you can get your season started with, all of which will tolerate and in many cases thrive in our early spring conditions.
Vegetables
- Direct planting
- Potatoes: These tasty tubers can be planted once soil temperatures have reached a minimum of 40° F (although 50° F and up is ideal). Mid- to late-March is a great time to plant, especially if you can provide a little extra protection during cold snaps with a cold frame or even a nice thick layer of straw mulch. Plant in well-drained soil, as they don’t enjoy overly wet conditions.
- Onions & Shallots: Onions & shallots are easy to grow and early to plant. You can them from seed as soon as the soil can be worked, although they are more commonly grown from sets (the baby bulbs that grow into mature onions and shallots), which can be planted in early- to mid-March. Bare root onion plants (seedlings which already have the green shoots started) can be started around the same time as sets.
- Peas: Peas should be planted when the soil is still cool, before days get too hot. Late March is ideal. Be sure to use a legume inoculant when planting. Inoculants encourage the formation of high-nitrogen nodules on plant roots for richer soil, bigger plants, and better yields.
- Garlic bulbs: While fall is the ideal time to plant garlic, you can still enjoy these delectable plants when planted in spring (just don’t expect the cloves to grow as big as fall-planted crops). Plant the cloves as soon as the soil is workable in well-draining soil and give a nice cover of mulch.
- Plant with row cover or cold frame
- Brassicas (cabbage, broccoli, kale, cauliflower, and more). These nutritious and hardy plants can be started quite early with some protection. Start seeds indoors to take advantage of warmer soil for quick germination, and then transplant outdoors where they will thrive before summer heat sets in.
- Lettuce: Lettuce is a surprisingly tough plant. Sown directly in rows in the garden, these leafy greens will thrive in cooler spring temperatures. I’ve had luck letting a few plants bolt (flower and go to seed) in the fall, with many seedlings sprouting naturally the following spring! Plant successive rows a few weeks apart to keep fresh lettuce coming in throughout the growing season and on into fall.
- Spinach: This deep green leafy plant is a great source of iron and grows well when sown directly into your garden. Grows best in cooler temps, as it tends to bolt quickly once warmer weather arrives.
Annual Flowers
- Pansies (including Johnny Jump Ups and Violas): Plant pansies as early as mid-March for a blast of early spring color. These flowers are exceptionally hardy, often surviving the winter with a bit of mulch and protection from drying winds. Even if they suffer frost damage from a particularly hard freeze, they typically bounce back and continue to bloom until mid-May. As a bonus, they will bloom again in the fall once temperatures cool, and can reseed (though so much as to be invasive) if allowed, spreading their delightful color around the flower bed.
- Snap Dragons: These incredibly unique flowers produce spikes of brilliant flowers that are aptly named for their dragon-shaped petals that can be squeezed to make their “mouths” snap open and closed. Also known to lightly reseed, these are always fun to find popping up through the snow in unexpected places.
- Ornamental Kale & Cabbage: Also known as flowering cabbage and kale, these ornamental versions of their vegetable counterparts have intensely colored foliage in smoky blues, whites, pinks, and purples. Purchased and planted as starts, they are very cold hardy and can go in the ground or in planters as early as mid-March.
- Ranunculus: Densley petaled “cabbage” type blooms are far tougher than they look. The fleshy flowers and green foliage look like something out of a still life painting. Not as cold hardy as some annuals, these are best for mid- to late-April planting.
Perennials
Nearly all perennials can be planted as soon as the ground has thawed enough to be worked, as long as the plants are dormant when planted. Because these plants would normally spend all winter in the frozen soil, early spring is actually an ideal time to plant them. As they have no active foliage, their exposure to transplant shock is greatly reduced, meaning they often perform better in their first year than they would if they were planted even a few months later. Plus, you can find some pretty great deals on early-season perennials, including our Perennial Palooza Sale.
Trees & Shrubs
Much like perennials, most trees and shrubs can be planted quite early, as long as they’re dormant. If you’re planting evergreens, be sure to watch out for our late spring snows, which can be heavy to the point of damaging branches, and young evergreens won’t bounce back from damage as quickly as well-established ones.
Originally published on March 3rd, 2020. Updated on March 3rd, 2021.