Long Island Horticultural Society
What's Going on in the Garden
May To Do List
Begin hardening-off frost tender plants now including vegetables, herbs, perennial and annual flowers that have been started indoors.
Newly transplanted vegetable plants should be protected from cutworms with collars. Cut strips of cardboard two inches wide by eight inches long, staple them into circles and place them around the plants. Press the collar about one inch into the soil. These collars will fence out the cutworms and protect the stems of the vegetable plants.
Plant asparagus if you do not already have some.
(Late May into June) Plant members of the nightshade family.(Tomatoes, Potatoes, Eggplant)
By the end of this month, it should be safe to plant almost everything outdoors -tender annual flowers like impatiens as well as tomatoes, peppers, and eggplants. Houseplants, too, can be moved to a shady spot in the yard for their summer vacations.
Finish sowing seed for annuals.
Plant a row for the hungry and donate the food to your local food bank. Find a food pantry near you: https://ampleharvest.org/find-pantry/
To prevent them from wasting energy on producing seed, deadhead your spring bulbs after they are done blooming.
Once spring-flowering shrubs such as Japanese quince, forsythia, azalea, lilacs have flowered you can cut them back.
Fertilize your plants.
Deadhead pansies and primroses after they have finished flowering.
Stay ahead of your weeding chores: Once temperatures soar, weeds and/or invasive plants can quickly get ahead of you.
Turn over your compost pile, or, if it has already broken down, use that compost in the garden and start a new pile.
Be on high alert for insect pests and diseases. These include, but are not limited to, aphids, asparagus beetles, cabbage worms, cutworms, scale, snails, slugs, leaf spot, mildew, and rust.
Get those lawn mowers ready , sharpen the blades, check/change the spark plugs, oil and air filter.
The grass will shoot up in May so get mowing now and do it every week if possible. If you get caught out and discover a jungle where the lawn used to be, raise the height of the cut on the lawnmower as far as possible – ideally you shouldn't cut more than a third of the grass blade at once. Then with the following cuts, gradually bring it down to normal.
Pinch mums and asters to encourage compact growth. Stop pinching by July 4.
When pruning, save long stems to use as stakes.
Hill Potatoes and Corn. Hill up soil around corn plants and top dress with a high nitrogen fertilizer.
Feed the soil around your roses if you haven't already. Roses should be getting ready to put on their first bloom, and they are heavy feeders.
Continue harvesting cool-season crops like asparagus, peas, and leafy crops. Keep an eye out for groundhogs and rabbits so that they do not get to your harvest before you do.