By Jennifer Fairfield, owner of The Garden Mill
May, just like every other month in Michigan, can definitely be “unpredictable,” but it is also the month when gardening really gets going around here. So, get your tools ready, and get to work – there’s lots to do this month.
Vegetables and herbs:
You can still plant potatoes and onions early this month. Vegetable seedlings that also can be planted early this month, if you haven’t yet, include broccoli, cabbage, kale, and head lettuce.
Parsley, thyme, sage, and oregano seedlings can be planted early in the month. Other herbs, such as rosemary, basil, cilantro, and dill should wait until all danger of frost has passed. Basil especially should not be planted too early, as it doesn’t do well in temperatures under 50°.
Seeds to plant early this month, if you haven’t already, include leaf lettuce, spinach, carrots, radishes, and beets.
Corn can go in soon, but beans should wait until about mid-month, if the soil has warmed up enough. It’s important to plant seeds when the soil temperature is right for that type of seed, because every seed has a temperature range at which it will germinate. If the soil is too cold or too hot, you’re just wasting the seeds. The University of California’s Extension Service has information on germination temperatures for many vegetable garden plants. A soil thermometer takes the guess work out of getting the timing right.
If you are starting your own plants, it’s time to start your squash and cucumber seeds indoors, so that they are ready to transplant outside at the end of the month. However, seeds for these and others, such as pumpkins and melons can be planted directly in the garden around the end of the month, and will do just as well.
Once the soil has warmed up to above 60° and nighttime temperatures are consistently above 50°, it’s safe to plant tomato, pepper, eggplant, squash, and cucumber seedlings. Around here, that typically means about the time of Memorial Day weekend. If we get an early warm-up, you might be able to get some of those in sooner – just be sure to have something available to cover them with if we get a cold snap, as low temps can hurt these tender plants. Lightweight frost blankets are best – they keep the warmth in without being so heavy that you risk harming the plants.
Flowers:
Now is a great time to get a jump on weeds, before they get out of control. The rain that we are expecting early in the week should make pulling weeds a lot easier, which is really good, because I have a bunch to get out of my flower beds.
Most perennials can be planted any time now – sooner is even a little better than later, as you want them to have a chance to get well-rooted before the hot, dry weather sets in. This is also a good time to divide late-spring and summer-blooming plants.
Plants that have outgrown their space or are getting bare spots in the centers should be dug up, divided, and replanted. However, if the plant is in flower now, wait until fall to transplant it. If you’re not sure how to divide plants, Fine Gardening offers some tips to help.
It’s still a little too early to plant most annuals. By about mid-month, it should be OK, depending on the temperatures. Remember, all the annuals available now have been living in heated green houses. Putting them in the ground right now would only shock them and slow their growth. Like our warm-weather veggies, for annual flowers, it’s better to wait until the soil has warmed up to at least 60° and nighttime temperatures are consistently above 50°. Planting of annual seeds should wait until the danger of frost has passed.
Patio pots and hanging baskets can be put out now, but you will want to bring them inside at night (an attached garage is fine), if the temps are dipping below about 40°. Keep an eye on watering your container plants – if it’s sunny and/or windy, they will dry out more quickly than plants in the ground.
(Part two of this column will publish tomorrow.)
