How to Start Seeds Outside in March for Cool Weather Vegetable Crops
Mar 01, 2023 ● By Tiffany Hinton
Photo credit: Megan Holly Photography
Are you ready to get your garden started early this year and enjoy
just-harvested cool weather veggies? If so, a great way to jump start your
spring backyard garden is by directly sowing crops like kale, spinach,
radishes, lettuce, peas and more in an easily constructed, temporary and
affordable low hoop house.
In March, the days grow longer and the sun angle is higher in the
sky, allowing the spring sun to start warming the soil. This a great thing for
early spring gardeners, because warmer soil temps and sunnier days will allow
cold seeds (also called cole crops) to germinate and begin
to grow, even if there are still a few nights with frost or a light freeze. Using
a low hoop house or floating heavyweight frost cloth over the planted beds will
allow them to grow even when the temp drops overnight. Community Sponsored
Agriculture (CSA) growers and local greenhouses use this technique to get an
early start growing their crops for the start of farmers market and farmstand season.
Construct the Hoop House
Two simple methods to plant seeds earlier in the season are cost-effective
and easy to add to your backyard garden. Both methods can be done for under
$100. A hoop house will help to warm the soil and also protect the seeds and
tender young plants as they sprout.
The first way to construct a low hoop house using half- inch PVC
pipe cut into 10-foot lengths that will flex to create an arch. The PVC ends
can be pushed into the ground directly or fixed to an existing raised bed using
pipe hanger straps. Place the PVC arches approximately three feet apart to form
a tunnel, then drape the PVC with heavy plastic drop cloth or heavyweight frost
cloth. Secure with clamps or zip ties to create a simple and low-cost low hoop
house for the seedlings to easily grow with protection from the overnight
cooler temperatures and any late season snow.
Another option is to use the floating cloth method to protect
tender seedlings and create a greenhouse effect. This methos works well for
raised beds and can also be used for seeds directly sown into the ground. Once
you’ve planted the seeds, carefully place the floating row cover cloth over the
ground and secure the edges to keep it from blowing away. You can use landscape
staples, small rocks or bricks that will also work well. You can purchase
floating row cover cloth online in a variety of weights for spring sowing and
also for protecting tender crops in summer from sunscald, insects, birds, heavy
rain or late-season frost. Johnny’s Seeds sells
frost cloth in 10-foot by 50-foot packages that can be cut to size using
scissors for under $40. Gardener’s Supply Company is another good source, and if you need a larger amount, check
out Greenhouse Megsatore.
Select the Right Seeds
The second thing to consider for spring planting success is
choosing seeds that will germinate in cooler temperatures and can be directly
sown. These include kale, spinach, radishes, peas, and several varieties of
lettuce. Look through the seed catalogs for additional crops that can be direct
sown before the frost in the culture section of the plant description. Local independent
garden centers and nurseries, like Jung Garden Center in the Madison area of
Wisconsin, also have garden experts who can assist with selecting seeds that
will thrive in the early season.
Don’t Forget the Compost
Third, consider adding a 2-inch layer of mushroom compost (or your
own backyard-produced compost) from your local independent garden store to the planting
bed. Compost provides two bonuses. First, it will naturally create heat as the material
continues to decompose back into the soil, creating a nourishing environment
for the plants throughout the season. Secondly, planting the seeds directly
into the compost layer avoids the need for any tilling, preventing soil
disturbance and saving the gardener the work of turning hard, pre-thaw soil in
late Spring.
If you are interested in learning how to build the low hoop house
from PVC or looking for professional help with your garden design and plan for
this summer, Tiffany Hinton, owner of Cultivating Guts, offers personal garden consultations. Hinton will be hosting a live, full
day immersion retreat on Earth Day, April 22, where she will be sharing
knowledge and guiding others in hands-on sessions on garden planning,
biodynamic gardening and raised bed building among other topics.
Visit CultivatingGuts.com for
more information.