Early Spring Planting of Vegetables

We often associate our vegetable gardens with the heat of summer, and there are certainly many popular vegetables, like tomatoes, squash, and peppers, that thrive in the summer heat.  However, many vegetable crops prefer the cooler weather of spring. These cool-season crops thrive in temperatures in the mid-50s to low-70s, and most will even tolerate a light frost.  This makes them prime candidates for early spring planting.

Planning for an early spring vegetable garden is a great way to extend the harvest season and grow high-quality vegetables. To get started, you'll need seeds and a calendar.

Planting radish seed By IndrePau AdobeStock
Cool-season vegetables, like radih can be planted in early spring  (1)

It's All About Timing

Timing is everything when planting an early spring garden. If started too late, vegetables will not have adequate time to produce a crop before the heat of summer arrives. Cool-season crops decrease in quality with warm temperatures. For example, radishes will be more fibrous with an unpleasant taste when they grow in warm temperatures.  Many cool-season vegetables, like lettuce, will bolt (flower), which reduces their quality.  Other cool-season crops, like peas, will see their growth and production drastically diminished.  

Cool-season vegetables can be planted once soil temperatures reach 50°F.  When soil temperatures are lower, seed germination is poor.  In Iowa, this means cool season vegetables can be planted as early as early to mid-April in central Iowa. (approximately one week earlier in southern Iowa and one week later in northern Iowa).  

Some cool-season crops, like lettuce, radish, and spinach, will mature and be removed from the garden by early to mid-June.  Others, like Brussels sprouts, cabbage, and onion, will stay in the garden and be harvested in mid to late summer (and some will grow until the cool fall season arrives, only to be harvested late in the fall.

Many cool-season vegetables are started by seed, but others are best transplanted into the garden.  Broccoli, lettuce, and cabbage are a few examples of cool-season crops that should be started indoors 6 to 8 weeks before planting.

What to Plant

lettuce with frost By helenedevun AdobeStock
Cool season crops can handle a late spring frost without damage.  (2)

Vegetables can be put into two groups based on their length to maturity.  Fast-maturing vegetables are in the garden early and out by early to mid-summer.  These crops can easily be interplanted with warm-season crops like tomatoes or melons, which only get large long after the cool-season vegetables have been harvested and removed.  These fast-maturing crops can also planted in succession.  By planting a portion of the crop every 1 to 3 weeks, the harvest can be spread out and enjoyed over a longer period, helping to avoid harvesting bushels of produce all at once.   Many of these fast-maturing vegetables are also good candidates for a second planting in the fall.

Long-maturing vegetables are often planted later in the spring and remain in the garden through the summer.  Some, like cabbage, are harvested mid to late summer, and others, like parsnips or Brussels sprouts, remain well into the fall.  These crops tend to improve in quality, size, and flavor with cool fall temperatures and are often harvested after the fall frost.

Some choices for vegetables that can be planted in the early spring in Iowa include:

Fast-Maturing

VegetableDays to MaturityNotes
Beet50-70Stagger planting every 4 weeks, greens can be harvested earlier
Lettuce, Leaf45-60Stagger planting every 3 to 4 weeks
Green Onion/Scallions*30-50 
Kale55-75 
Kohlrabi55-70can be grown by direct sowing or from transplants
Peas55-85 
Radish25-40Stagger plantings every 7 to 10 days
Winter Radish/Diakon45-70 
Spinach45-60 
Turnip45-70greens can be harvested earlier

Long-Maturing

VegetableDays to MaturityNotes
Brussels Sprouts80-90Harvest after the fall frost
Broccoli60-65 
Cabbage60-90 
Carrot60-80Stagger planting every 3 to 4 weeks
Cauliflower55-80 
Collards60-80Harvest greens into the fall
Leek90-100* 
Parsnip110-130Can be overwintered in the ground, mulch and dig before new growth starts in spring.
Rutabaga80-100 
Swiss Chard60-65can be grown by direct sowing or from transplants

* Days to maturity is for those vegetables started from plants or sets

Peas sprouting in early spring garden By Hans AdobeStock
Plant cool season vegetables early, when soil temperatures are 50°F.  (3)

Planting

Cool-season vegetables that are direct-sown into the garden can be planted once soil temperatures reach 50°F.  This is typically early to mid-April in Iowa.  Never work in the garden when soils are overly wet.  When planting, rake and remove weeds so the seed has good soil-to-seed contact.  Seeds may need to be watered periodically.  Spring tends to have normal rains so only water when soils are dry.  

Those crops that are longer to maturity, such as broccoli, cauliflower, or Brussels sprouts, should be started indoors and transplanted in the garden.  For many of these crops, seeds can be sown indoors six to eight weeks before the planting date and transplanted outside as late as mid-May.  

Additional Information


Photo credits: 1: IndrePau/AdobeStock; 2: helenedevun/AdobeStock; 3: Hans/AdobeStock

Authors:
Last reviewed:
October 2024