Gardening Tips from The Webster Arboretum

A Gardening Checklist for May

It’s May and the world is awakened. Cherry blossoms scatter on the wind, just as crabapples and dogwoods begin to flower. New York sees a wide variety of flowers blooming, including lilacs, magnolias, and trees such as cherry, dogwood, and redbud are blossoming.   For gardeners, May is an exciting and busy month. According to the Farmer’s Almanac, on average, the last spring frost occurs on May 7th in our area.  So, by mid-month, it’s pretty safe to plant out frost-tender annuals and, of course, there’s still lots of direct sowing to be done.

First things first. Make sure your beds are prepared. 

Thoroughly weed your garden bed to avoid competition with seedlings. Shape the bed and tidy up the edging.  This is an excellent time to test your soil.  Soil tests can be conducted by The Cornell Cooperative Extension in your area.  This helps you to identify nutrient deficiencies and adjust pH levels and will provide recommendations for soil management and improvement. 

Establish where you will be walking and tending to your crops by adding pavers, stones, or planks to indicate the path. Be sure the paths easily allow you to weed and care for the plants.

Think before you plant

Most vegetables grow best in full sun and in soil with a pH level between 6.0 and 7.0. The soil should be well-drained, but moisture retentive. But have you considered exactly where to put what?

Consider compatible and non-compatible plant pairs. Several vegetable pairings are known to benefit each other when planted together, offering advantages like pest control, improved growth, and increased yields. Some examples include tomatoes and basil, onions and carrots, and beans and corn. Other compatible plantings include lettuce, carrots, nasturtiums, marigolds, radishes, beans, corn, dill, cucumber, tomatoes, basil, beetroot, chives, and garlic.

But there are vegetable combinations that should not be planted together due to competition for resources, pest/disease issues, or allelopathic effects. Allelopathic plants are those that release chemicals into their surroundings that inhibit the growth of other plants. An example of this is Fennel, which can produce allelopathic chemicals and inhibit the growth of other plants in the vicinity.

Some examples of non-compatible plants include tomatoes and brassicas (broccoli, cabbage, cauliflower). Brassicas are heavy feeders and compete with tomatoes for nutrients, potentially stunting tomato growth, and brassicas can also attract pests that might harm the tomato plants. Other non-compatibles include: 

·       Onions and asparagus should not be planted in the same area, as onions can inhibit the growth of asparagus

·       Tomatoes and potatoes are both susceptible to blight, and planting them together can increase the risk of infection

·       Corn and tomatoes are both heavy feeders and can deplete the soil of nutrients and thus decrease yield

When considering the above, successful vegetable gardening can be complicated and needs a thoughtful garden plan. 

After the last frost you can plant a wide variety of vegetables and don't forget your herbs and summer flowers. Hold off tomatoes, peppers, and other warm season crops. Some vegetables thrive in warm soil. They generally require soil temperatures of 60 degrees or higher for optimal growth. Planting warm-weather vegetables too early can lead to stunted growth, slowed development, and increased susceptibility to diseases. 

Hardening Off

When purchasing annual flowers, vegetable plants or preparing your very own seedlings for the garden, don’t forget to ‘harden’ them. Hardening off plants is the process of gradually exposing seedlings or transplants to outdoor conditions, like sunlight, wind, and temperature fluctuations. Well-hardened plants are better equipped to thrive in the garden, leading to healthier growth and higher yields. 

To harden plants off, gradually expose them to outside conditions by placing them in a protected area (away from strong sun or wind) and gradually, over a week or two, increase exposure to conditions that will be similar to the outdoor environment in which they will be planted.  If nights are cold, you should bring them in or cover them with row covers. If you have a cold frame, you can harden them off there.

Transplanting

Pick a mild, cloudy afternoon to give your seedlings a smooth transition. To successfully move plants into your garden, start by watering them well beforehand, then dig the hole for the new location and carefully remove the plant with its root ball intact. Gently place it into the prepared hole, making sure the root ball is not too deep or shallow.  Finally, fill the hole with soil, firm it down, and water thoroughly. Be sure to pay attention to plant spacing. This should be based on the mature width of the plants, with the centers of the plants spaced half their eventual width apart. Row spacing should be determined by the mature size of the plants and the type of garden setup such as raised beds or ground gardens. 

Because their roots systems are not yet established, transplants require frequent, but shallow watering at first. Don’t expect spring rain to do all the work.  As plants mature, the inverse is true: less frequent, but deeper watering is best.

To mulch or not to mulch?

Mulching your vegetable garden is good practice, but it's important to choose the right type of mulch and apply it correctly to maximize its benefits and avoid potential drawbacks. If mulch is applied too thickly, it can prevent oxygen from reaching the roots, leading to root rot and plant death. A 2–3-inch layer of mulch is generally recommended but be sure to leave a small space between the mulch and plant stems to prevent fungal growth.

Mulch prevents loss of moisture from the soil, suppresses weed growth, reduces fertilizer leaching and cools the soil. Mulch also serves as a barrier between the plant and the soil, helping prevent fruit rots that sometimes occur when vegetables touch the ground. If direct seeding, it's important to wait until the soil is warm and the seeds or seedlings have emerged before applying mulching. 

Enjoy yourself and have fun getting your hands dirty.