Despite the snow of last week, spring is in the air. Flower buds are plump and breaking their winter dormancy, and spring bulbs are pushing their way out of the ground, sometimes right through the snow. It is at this time of year I get out all my seed packets to see what I have and what I need to purchase.
On the back of the packets are planting instructions. Sometimes there is a map of the United States broken into zones, and depending on which zone your state falls into, there will be a chart telling you when its best to plant that seed outside. Other packets are more specific, saying such things as "best planted two to four weeks before average last frost," as stated on a package of Arugula, a cool-season crop. The packet of oregano, a warm season crop, recommends planting two to four weeks after the last frost. In Broomfield and along the Front Range the average last frost is mid-May. To determine appropriate planting date, count the weeks forward or backward from May 15.
The packet with the most curious planting description was Swiss chard. It said to plant in spring, when the ground can be worked.
Technically the ground can be worked now, but working soil — whether digging, tilling or walking on it — that is too wet can damage the soil structure. Tilling wet soil can destroy the spaces between soil particles, restricting air and water movement. Compacted clumps of wet soil become clods that don't allow roots or moisture to penetrate. The lack of air spaces limits root growth and as a result, plants fail to thrive. Water either sits on the surface of the compacted soil or runs off rather than soaking in.
A simple hands-on test will help determine if the garden soil is too wet, too dry or just right to be worked.
Pick up a handful of soil and squeeze it gently into a ball. Then apply light pressure to the ball with your finger. If the ball breaks apart easily into loose pieces, the soil is dry enough to till. If pressing on it flattens the ball, the soil is too wet. Wait a few days and test again.
If the soil won't hold together to form a ball, it might be too dry to easily cultivate. Water the area thoroughly. If the water stands rather than soaks in, use the cycle and soak method of watering to avoid wasting water. After soaking the garden, wait a couple days and test again.
For more information on soil structure and warm- and cool-season vegetables refer to Colorado State University Extension garden notes No. #213 and No. 720 (cmg.colostate.edu).
Colorado State University Extension in the City and County of Broomfield provides unbiased, research-based information about 4-H youth development, family and consumer issues, gardening, horticulture and natural resources. As part of a nationwide system, Extension brings the research and resources of the university to the community. The Broomfield County Extension office is at 1 DesCombes Drive, Broomfield, 80020. For information, call 720-887-2286.