By Katie Markheim
Nebraska Extension Master Gardener
As the planting season gets underway and garden centers beckon you to buy, remember that new transplants need some extra care to transition from their cozy greenhouse environments to the outdoor garden. Both the garden and landscape are investments of time and money that can be beautiful, functional, and satisfying living spaces. Make use of the hardening off period for your new transplants, and consider the following when creating your outdoor garden or living space: site preparation, plant and seed selection by hardiness zone, watering habits, and staking, protecting, and mulching. These are aspects of integrated pest management and a great way to ensure the growth and longevity of your investment.
Once you are ready to move on to planting your bedding plants and garden vegetables, you will need to harden them off before transplanting. There are a couple of ways to do this, the first is to pick up your garden plants from greenhouses and then harden them off before planting. Place new plants outside, in a protected area. Do this daily to allow them to “toughen up.” With each additional day, move them further out into full sun exposure and in breezy conditions. This will strengthen the plant with less chance of wilting. Be sure to do this two weeks before transplanting. If threats of light freezes remain, be sure to bring plants in. Once soil temperatures reach a minimum of 60 degrees Fahrenheit, it should be safe to plant those tomatoes, peppers, cucumbers, and squash plants.
The second way to get your garden or flowers outside is to build a cold frame in your backyard or acreage. Cold frames are the smallest, simplest, and least expensive structures for protecting plants. They can be constructed using a wood frame box set on the ground with glass, acrylic, or polyethylene plastic covers. Kits with aluminum framing and poly sides are also available for purchase. The frames capture the daytime heat through solar energy and use it to heat the growing area. The low structural design retains heat, providing warmer nighttime air temperatures, preventing cold injury before getting those plants into the ground. By using a cold frame, spring planting can occur three to five weeks earlier, aiding in a potentially better and faster hardening-off process.
While out in the garden or flower beds, don’t get too aggressive with cleaning out leaves, and check your hoses and sprinklers before hooking them up. This is to help slumbering insects, especially beneficial insects present in what they consider their overwintering habitat. There is so much life in the overwintered leaves and stems. Pollinators such as bees (leaf cutter), butterflies (Regal Fritillary), or moths (Luna Moth) are being sheltered beneath the leaf litter. An added benefit to holding off on garden or flower bed clean-up until late May in western Nebraska is the potential to protect plants, especially those starting to green up, from late frost damage. So, give it a rest and let your garden sleep in. Wait to tidy up your old flowers, stems, and plants until Spring when weeks of 50 degrees Fahrenheit or above are becoming the norm.
It may seem silly to think about the first freeze of the season already as we near the summer months, but for many gardeners, it’s a consideration as they look to planting early enough to capitalize on yield at harvest before the next visit from Father Winter. Ever wonder how to calculate the days to frost? Simply put, start with your median last frost date, and count back the number of weeks it takes the plant type to mature. Then, count back two more weeks to account for the hardening timeline to know when to plant various vegetable crop seeds indoors. According to UNL CropWatch, the median frost date generally falls between September 11th and October 10th for Western Nebraska, which means you could have sprouts in your house as early as March.