Unlock the Secrets of Successful Seed Starting in Colorado: A Guide for April Planting Enthusiasts
- Crystal Lbussey-dutton
- Apr 9
- 4 min read
Updated: Apr 20
April signifies a crucial moment for gardeners in Colorado. As winter yields to spring, it’s time for passionate gardeners to jumpstart the growing season by sowing seeds indoors and directly planting early-season vegetables and greens. Whether you’re a gardening expert or just starting out, this guide offers practical information to help you make the most of your April planting adventure.
With the last frost usually occurring around mid-May in Denver, now is the perfect time to prepare your garden for a fruitful harvest of vegetables and beautiful blooms.
Indoors: Preparing for Transplanting Later
The Essentials of Indoor Seed Starting
Starting seeds indoors gives your plants a significant advantage. By nurturing them in a controlled environment, you ensure they have the best chance to thrive before facing Colorado’s unpredictable spring weather.
Broccoli, Cabbage, Cauliflower, & Brussels Sprouts
If you’re gardening in Colorado’s cooler climate, make sure to start seeds for broccoli, cabbage, cauliflower, and Brussels sprouts. Aim for 6-8 weeks before the last frost date, which is around mid-May. Thus, April is just the right time.
For example, if you plant two broccoli seeds per cell in a seed tray, thinning them to one later can yield about 10-12 broccoli heads per plant by mid-summer, providing enough for fresh meals and freezing.
Onions
Don't overlook onions. Starting onion sets or seedlings indoors will allow them to establish well. After about 10-12 weeks, you will enjoy sweet, homegrown onions rich in flavor for countless recipes.
Parsnips
Parsnips are also worth considering. Planting these seeds indoors not only protects them from fluctuating temperatures but also sets you up for a successful harvesting season. Each parsnip can grow up to 12 inches long, making them a delicious addition to soups and roasts.
Direct Sow: Planting Outdoors in April
Early Planting Strategies
In addition to indoor sowing, April is ideal for direct sowing many early-season veggies and greens.
Arugula, Peas, Spinach & Radishes
Kick off your outdoor sowing with arugula, peas, spinach, and radishes in early April. These crops enjoy cooler temperatures and can establish before the heat of summer. For instance, if you plant 10 feet of peas, you can expect an impressive yield of around 5-7 pounds of sweet pods per harvest.
Kale, Lettuce, Swiss Chard, and Other Leafy Greens
Consider planting kale, lettuce, Swiss chard, and other greens throughout the month. These leafy powerhouses thrive in cooler weather and provide continuous fresh produce. If you stagger your sowing every two weeks, you can collect fresh greens for salads over several months.
Beets, Carrots, and Turnips
For beets, carrots, and turnips, aim to plant them about four weeks before the anticipated last frost. Beets, for instance, can grow to 3-4 inches in diameter and can provide you with a vibrant harvest for salads.
Chives, Mustard Greens, Parsley, & Tatsoi
Be sure to plant chives, mustard greens, parsley, and tatsoi in early to mid-April. These hardy greens not only elevate dishes with flavor but are also easy to grow. Parsley, for instance, can thrive for more than two growing seasons, making it a reliable choice.
Kohlrabi
Lastly, you can plant kohlrabi in April. This unusual vegetable offers crisp texture and a mild flavor, making it a great choice to diversify your harvest.
Flowers: Add Color to Your Garden
Pansies, Snapdragons & Sweet Alyssum
April is perfect for sowing flower seeds to brighten your garden space. Start with pansies early in the month, which come in a range of vibrant colors.
Later, consider planting snapdragons and sweet alyssum. These stunning blooms will not only enhance your garden's visual appeal but also attract beneficial pollinators.
Perennial Flower Seeds
April offers a great opportunity to begin planting seeds for perennial flowers. Consider varieties like columbines, delphiniums, hollyhocks, and daisies. These perennial favorites will return year after year, enhancing your garden with color and vibrancy.
Timing is Key: Know Your Frost Dates
Timing is everything in Colorado gardening. Understanding your local average last frost date significantly impacts your seed starting success.
Consider Your Last Frost Date
Make sure to research your local climate to maximize your gardening efforts. Knowing the last frost date allows you to plan effectively and ensure your tender plants survive.
Check seed packets for specific planting times to make your growing season smoother. For instance, knowing that your area’s typical last frost is mid-May means you can confidently plant warm-season seeds indoors in early March.
Warm vs. Cool-Season Crops
Understanding the difference between warm-season and cool-season crops is critical.
Warm-Season Crops: Start vegetables like tomatoes, peppers, and eggplants indoors 6-8 weeks before the last expected frost.
Cool-Season Crops: Crops like lettuce, spinach, and kale should be started about 4-6 weeks earlier.
This knowledge will help you organize your planting schedule effectively, increasing your chances of a bountiful harvest.
Succession Planting for Year-Round Harvests
One of the best techniques for extending your harvest is succession planting. This method involves sowing seeds in intervals, allowing for a continuous supply of produce throughout the growing season.
Implementing Succession Planting
Instead of planting everything at once, stagger your sowing every few weeks. This method not only provides an extended harvest period but also keeps your garden healthy and productive. You will always have fresh veggies on hand for your meals!
Happy Gardening in April!
April in Colorado is the perfect time to unleash your planting enthusiasm. With the promise of spring ahead, you can start seeds indoors for future transplanting and directly sow many of your favorite early-season vegetables and greens. The possibilities for Denver gardeners are limited only by imagination and dedication.
By knowing which plants to start indoors versus what can be sown directly, as well as considering local climate factors, your gardening efforts are sure to flourish. Embrace the joy of seed starting this April, and watch your garden flourish with a colorful array of flavors and beauty.
Happy gardening!
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