15 Garden Tasks To Do in May

May is a great month for gardening in almost every zone. With a few exceptions, most of the U.S. is past the threat of frost. Those of you in zone 2 might want to hold off on a few items until the second half of the month. Everyone else is safe to get rolling on that summer garden prep.

Several things are happening in the garden right now that make it a prime time for getting things underway in cooler climates. The ground is warming, but the air is still cool —a combination that reduces stress and promotes rapid root and top development in most plants. Pair those things with increasing daylight hours, and May turns into a major growth period.

The work that you put in now will make a difference in the way your garden looks and produces in the coming season. Since the weather is so lovely, why not get out there and tend to your beds to get them in order? Here are some tasks you can complete now to achieve great results this summer. 

Assess Your Perennials

One of my favorite spring garden activities is wandering around the garden to see how everything is looking after the cold weather has passed. My region experienced some unprecedented winter weather this year. It snowed in North Florida for the first time since 1989. This wasn’t just a dusting either. There was a snow cover of four to six inches!

With unpredictable weather patterns, our plants may rebound differently from year to year. A particularly cold winter may mean certain perennials get off to a slower start. If you had a warm winter, your bulbs may have popped up too soon or didn’t look their best this spring. 

By May, in most regions, you should get a fair idea of whether your perennials are going to come back this year, or you’ll need to replace them. It should also become clear which plants suffered any cold damage and need some TLC. With spring in full swing, the garden has a lot to tell us about how it is coping with the current weather conditions. 

Take a stroll through your space and see how things are growing. Make note of which perennials didn’t make the cut, and address any damage the ones that returned sustained this winter. Take care of these areas by clearing away dead and damaged foliage and branches to make way for new, healthy growth, and in some cases, new permanent residents. 

Test Your Soil

If you haven’t done so already, May is a good month to test your soil. You should do this before you do the bulk of your summer planting, so in warmer climates, this time may have passed. That doesn’t mean that you should skip it altogether. Go ahead and test it either way to get an idea of any potential hurdles that may arise.

A soil test reveals several key insights. It tells you the composition of your soil, as well as how fertile it is. It helps you understand nutrient levels and whether the pH is conducive to the plants you want to grow, as well as those already in the garden. 

Once you have the results of your soil test, it should be easy to make the necessary adjustments. Amend soil that is lacking in nutrients with compost, manure, or slow-release fertilizers. To adjust the pH, you can add lime or wood ash to make it more alkaline, and add compost, sulfur, iron, or aluminum sulfate to make it more acidic. 

Soil pH is important as it determines how nutrients break down and become available to your plants. Some need acidic soil as this breaks down nutrients like iron and magnesium in a form that they can use. Basically, a soil test gives you a clearer picture of what will grow there, and what you’ll need to do for what won’t.

Prune Spring-Blooming Shrubs and Trees

Once your spring bloomers finish for the year, it’s time to give them all a good pruning. This is especially true for those that bloom on old wood. Those that bloom on new wood wait until the plant comes out of dormancy to develop buds on the new growth. 

Many trees and shrubs that flower in spring form buds the year before, on mature wood. The best time to prune these plants is immediately after they finish flowering. This gives them ample time to put on new growth, for that to mature, and to set buds before winter dormancy. 

For those trees and shrubs that bloom on new growth, you can do a light clean-up to encourage growth over the summer. Deadhead any remaining flowers and give a once-over to remove any dead or damaged wood. Otherwise, leave the major pruning of these for late winter. 

If you have repeat bloomers, like many roses, gardenias, hydrangeas, and others, remove all of the branch tips that bloomed. This will encourage new growth and the formation of more buds, which will bloom later in the year.

Plant Frost Tender Bulbs

Spring-blooming bulbs are usually best planted in the fall. Many of them need a period of cold weather to initiate growth and blooming. Tulips, daffodils, and hyacinths all fall into this category. 

Summer blooming bulbs, like cannas, calla lilies, begonias, caladiums, and dahlias, are frost tender. That means you’ll need to dig them up in the fall and protect them from the cold in most climates. 

By May, your soil should be warming up, and the risk of the ground freezing is low. Planting these now gives them ample time to get established while the air is cool and the environment is less stressful. When in doubt of a late frost, you can wait another week or two past your last frost date. 

Support New Growth

Spring is a time for major growth, and those plants that are already in high gear may need additional support. Take a look especially at climbing vines and other plants that require support, and adjust these to promote a strong, healthy summer season. 

May is an ideal time to provide your garden with the support it needs to thrive throughout the summer. Ensure that proper supports are in place and that they can withstand the weight of each plant for the remainder of the growing season.

The purpose of supporting various plants is multipurpose. For one thing, it keeps them in a position that is aesthetically pleasing, allowing us to see them at an ideal angle. It also gives them protection from the elements. Even those that stand upright now may fall over in a strong wind or during heavy rain. Consider these now and provide them with the support they need and will continue to need. 

Harden Off and Transplant Seedlings

All those seeds you started in late winter should be nearly ready to move to their final homes. As long as that last frost date has passed, you should be ready to first, harden off your seedlings and second, transplant them outdoors. 

Hardening off is the process of toughening up your seedlings so that they will stand up straight and endure the outdoor conditions. Take the next week or two to gradually acclimate your seedlings to the outdoors. 

Don’t expose them all at once, even those that will prefer full sun. They will thrive best if you move them gradually and allow them to get used to outdoor conditions. 

Choose a warm, windless day and place your seed trays outside in a spot with indirect sunlight. Leave them there for several hours, and then increase this amount of time daily for about a week, possibly two. Move them closer to the light each day until they are in the exposure that you will plant them in. 

Once your seedlings are spending the whole day outdoors, it’s time to transplant. Plant them in the ground and tend to them for the next week or so to ensure they survive. After that, you can treat them as you would a mature plant. 

Plant Annuals

If you’re anxiously awaiting the perfect time to place those colorful annuals in the garden, good news! That time is upon us. Feel free to pay a visit to the nursery if you aren’t growing from seeds, in which case, it’s time to transplant. Select some beautiful annuals and add them to your growing garden. 

Fertilize

Depending on your climate, your garden is either in full swing or about to take off. Either way, it’s a great time to fertilize. All that growth requires nutrients, and you want the nutrients to be available when your garden needs them.

If you’ve done a soil test, you should have a good idea of what your soil is lacking and what it has plenty of. If everything is in good order, a balanced fertilizer is ideal for providing everything with the boost it needs. 

If your soil is lacking in one or more of the important nutrients, you want to replenish it in time for that growth phase. For instance, if your soil pH is too high or iron-deficient, you may end up with plants exhibiting chlorosis. 

Pinch Out Flowering Plants

This again hinges on your climate and the amount of growth your plants are already doing. Here in the South, I’ve been pinching my plants for a month or two already. If you’re in a cooler climate, it’s likely the perfect time. 

Pinching out your plants, both annual and perennial, is a way to encourage branching and fuller, bushier growth. More growth means more flowers, so for any branching plants, it’s a good habit to get into. 

When your plants have about three sets of true leaves, you simply pinch off the top set. This causes the buds on the lower nodes to branch. You’ll start to see these branches form in a couple of weeks. If you want to pinch again, wait until the branches have at least two sets of leaves. 

Remember that the later you wait to pinch, the later they will flower. However, while pinching will delay flowering, it will also increase the number of blooms, so it’s a trade-off, which, in my opinion, is worth waiting for. 

Look For Early Evidence of Pests

As temperatures rise and things start to come back to life, another issue emerges. It’s about this time that you’ll start seeing pests and their damage to your young plants. Young, tender growth is particularly susceptible. 

As a pollinator gardener, I have a tough time dealing with these insects because the same substances that eliminate them also harm the bees and butterflies. 

Some products are less harmful than others and have shorter lifespans. Opt for these gentler, more short-term products, and only treat those plants that are not yet in bloom, and are not close to others that are. Neem oil is a great choice for this time of year. Spray it in the early morning or evening, as it will dissipate some before the pollinators come out in the morning. 

Direct Sow Summer Vegetable Seeds

While you’ve probably long since gotten started on things like tomatoes and peppers indoors, there are those vegetables with large seeds and taproots that you should directly sow. Now that the ground is warming up, it’s time to get those planted. 

Directly sow things like corn, carrots, squash, cucumbers, peas, and beans. Sowing these directly is beneficial for their roots, which won’t go through the stress of transplanting. This all depends on your climate, though. Determine how many days you have until your first frost, and plant those varieties that mature within the time frame from now until then.

Set Up or Maintain Irrigation Systems

Since we are getting all of our plants in the ground, it’s a good time to go through and check out, or install an irrigation system. An irrigation system can go a long way toward conserving water and, in turn, saving money.

If you have an existing system, turn it on and check all connections to ensure they maintain their tight seals, preventing water from escaping. Check sprinklers to ensure they are functioning properly, and replace any fittings that broke during the previous season or appear worn out. 

If you’ve been on the fence in previous years about whether installing irrigation is right for your space, this is the time of year to make the call. Get things set up now to give your garden a solid start in the coming season.

Weed

It’s time for everyone’s favorite gardening pastime: weeding. You can just hear the excitement in my tone, can’t you? This is another task that hinges on your climate. If you live in a warm climate like I do, and you haven’t weeded yet, you’ve got your work cut out for you. Get it done now before things get completely out of hand. 

In cooler climates, those weeds will be popping up about now, and it’s prime time to tank them out. Weeds in your beds compete with your intentional plants for resources. Many of them rob nutrients from the soil. They use up water, and their roots can compete for space and nutrients. Once they get large enough, they may even compete for sunlight.  

No one likes weeding, but it is a necessary evil. Once it’s done, you will feel much better about your spaces, as the things you plant intentionally won’t have that competition, and it will be easier to see their growth and development. 

Mulch Beds

After weeding, it’s time to lay down mulch. If you mulch too early in the season, you risk holding in the cold. You want your soil to warm up so that the roots can get what they need for strong, rapid development. Soil temperature also determines germination. 

Mulching now, before the heat arrives, will insulate the roots and help retain moisture. Moisture loss is a more significant issue in the summer, as water evaporates more rapidly in the heat. Mulch will prevent that from happening.

Mulch also suppresses weeds by blocking the light. If you don’t weed first, you defeat this purpose. By weeding first, and then mulching, you will decrease the need to pull weeds long term. Mulch also breaks down and enriches the soil over time. 

Mow

This is one that I sit on the fence with. However, as I am in a warm climate, we practice no-mow March, but by April, we have to put some time and effort into manicuring the lawn. If you’re in a cooler climate, no mow May might be a thing, in which case, go ahead and hold off for the month.

If you delay mowing, you help pollinators and other members of the ecosystem. Hibernating insects and small animals find their home in piles of leaves and tall grasses for the winter. The earliest blooming flowers are important for pollinators, and often are the ones that pop up in your lawn. 

If you can manage to hold off another month in those cold climates, you’re doing a service to the ecosystem in your garden. If not, this is the time to get started.