Some plants endure beginning of season better than others

Q. I am new to Maine and would like to know when I can transplant the red bell peppers, tomatoes, cucumbers and lettuce plants that I started from seed outside. My pepper plants are 4 to 6 inches tall now, but I’m not sure how hardy of a plant it is for the Maine climate. I assume that once I have 2 or 3 leaves showing on my lettuce I can put them out, since they are cold-loving plants, but am unsure about the others. Thank you for your help. A new gardener and new Northerner, A.R., Chelsea.

A. In some respects, this is a difficult question to answer, because there are numerous ways to effectively lengthen the growing season in Maine. Through the use of season extenders such as cold frames, row covers and individual plant protectors, it is possible to stretch the season of growth significantly here in northern New England.

Let’s assume, though, that you’re not using season extenders. You’re right – lettuce (along with other greens and hardy, cold-loving crops such as broccoli, cauliflower and cabbage) can be set out into the garden earlier than some of our more tender plants. Most gardeners await the last frost-free date for their neck of the woods before setting out heat-loving seedlings such as peppers and tomatoes. To determine your local date, contact the Cooperative Extension office in your county. Some gardeners use the general rule of thumb that it’s safe to plant the garden after Memorial Day.

No matter what the plant or planting time, hardening off seedlings is one of the most effective ways to ease the shock plants endure when being transplanted to the garden. The process may significantly increase the survival rate and performance of a range of species. Hardening off is simple: For several days to a week before planting, set your plants outside in an area that is protected from intense light and wind. A vented cold frame is an ideal place for hardening off plants grown in the home or greenhouse.

The process of acclimating plants to the outdoors is an essential component of minimizing the severe environmental differences between the open garden and the highly regulated and protected greenhouse. Plants that do not undergo hardening off often suffer from water stress when set out in the garden. They may be ill-adjusted and poorly equipped to deal with the demands of the garden environment.

Q. Already this spring the deer have ravaged my garden. Can you recommend some plants that deer will not eat? – G.M., Swanville

A. Nothing is quite as aggravating as deer damage, is it? My neighbors and I have been experimenting with a number of tactics over the past few years, but I think the deer vastly outnumber us and we’ve enjoyed little success. Using plant material that deer don’t find too tantalizing may be one way to avert disastrous levels of damage.

Plants that are deer-resistant include ajuga, lady’s mantle, columbine, artemisia, aster, pigsqueak, bellflower, bachelor’s buttons, globe centaurea, sea lavender, iris, candytuft, ground phlox, rudbeckia, penstemon, scabiosa, lamb’s ears and oregano. Yarrow, thyme, catmint, salvia and lavender actually repel deer.

Using deer-resistant plants may help minimize damage, but the list of plants is disappointingly short. There are some products I’ve been alerted to that are apparently quite effective against deer. I’m researching them, so please stay tuned. I’ll report on what I find out about these deer repellants in a few weeks.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, RR1, Box 2120, Montville 04941, or e-mail them to dianagc@midcoast.com. Selected questions will be answered in future columns. Include name, address and telephone number.