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May is one of the most exciting months in the garden. The anticipation of planting season is building, seedlings are filling up the greenhouse, spring bulbs are blooming, and garden centers are finally reopening for the season. Here in Wisconsin, we still have the occasional frost threat hanging around, but warmer days are definitely on the way.
So what should gardeners be doing in May? Here are a few of the things I focus on this time of year in my own garden.
Give Seedlings a Nutrient Boost
By May, many seedlings have already used up the nutrients in their seed-starting soil and are ready for a little extra support. This is a great time to start feeding them with a liquid fertilizer to encourage healthy growth before planting outdoors.
I like using Espoma Grow because it’s gentle enough for young plants while still giving them the nutrients they need to continue growing strong.
Healthy seedlings now mean stronger plants later in the season.
Watch for Garden Pests Early
One thing I always keep an eye on in May is garden pests. Some years I barely notice any damage, and other years they seem to show up overnight.
This spring I started noticing slug damage on a few leaves before I ever spotted the actual culprit. I tried Sluggo for the first time, and thankfully I haven’t seen any new damage since using it.
Aphids are another common issue this time of year, especially on young seedlings and tender growth. When they show up, neem oil is usually my go-to solution.
Catching pest problems early can make a huge difference before plants really take off for the season.
Start Hardening Off Seedlings
As the weather warms up, planting season gets closer — but before seedlings move outside permanently, they need time to adjust.
Right now, your seedlings are living in pretty ideal conditions indoors or in the greenhouse. To prepare them for outdoor life, you need to help toughen them up a bit.
One easy way to strengthen seedlings is by using a fan to create airflow. It doesn’t need to be intense, but the movement helps strengthen stems so they can better handle natural wind outdoors.
The next step is hardening off. This means gradually introducing plants to outdoor temperatures and sunlight by taking them outside during the day and bringing them back in at night.
Some gardeners recommend hardening off for around 10 days, but I usually aim for about 5 days depending on the forecast and how stable the temperatures are.
Weed Garden Beds Before Plants Fill In
May is also one of the best times to weed garden beds.
While perennial plants and flowers are still small, it’s much easier to spot weeds before everything fills in for summer. The more weeds you remove now, the less maintenance you’ll have later in the season.
Weeding early also gives your plants better access to water, nutrients, and root space as they begin actively growing.
Refresh Garden Bed Edges
Another task I try to tackle in May is cleaning up the edges of garden beds.
I’m always amazed at how quickly grass starts creeping back into the landscape after winter. Touching up edges now helps gardens look cleaner and more defined throughout the growing season.
It’s one of those small gardening tasks that makes a surprisingly big difference.
Finish Planning Your Garden
By mid-to-late May here in Wisconsin, planting season finally begins. Before everything goes into the ground, now is the perfect time to finish planning your garden layout and make those final plant lists.
That’s one of the reasons I created The Garden Book. It includes grid paper for sketching garden layouts along with Seed & Plant Lists to help keep garden center trips organized and intentional.
Having a simple plan before shopping makes it so much easier to create a garden you truly love.
Enjoy the Season
May can feel incredibly busy in the garden, but it’s also one of the most rewarding times of year. Every seed planted, weed pulled, and flower bed cleaned up is an investment in months of beauty ahead.
As gardeners, we know the work is worth it.
Happy gardening!
