Gardening Jobs to Do in May

May is a crazy busy month. With days getting warmer and lengthening, the nighttime temperatures are still cold despite this. This month will see the last of the year’s frosts, allowing gardeners to start putting all those seedlings into the ground.

Despite the continued sowing and planting of seedlings, extra work is needed in the garden this month.

Each month’s Jobs-to-Do article has a common format, and this one is no different:

  • Garden preparation jobs to do.
  • Garden maintenance jobs.
  • Vegetable gardening jobs to do.
  • Fruit garden jobs to do.
  • Indoor and container gardening projects.
  • Ornamental garden jobs to do.
  • A summary of what gardeners should focus on.

Garden Preparation Jobs to Do in May

Cover crops filled with an assortment of plants.
May Garden Preparation Tasks – A Focus on Cover Crops

With longer and sometimes warmer days now here, this month is the perfect time to get your garden in order and ready for a season of enjoying your stunning outdoor space! Follow our guide and add the right pieces to your garden to create a beautiful area that works for you.

With Summer drawing nearer and the weather warming up, now is the ideal time to spend more outdoors and concentrate on preparing your garden for the remainder of the year. Remember our resolution in January to ensure we keep our soil healthy using cover crops this year. The two main contributors to healthy soil are soil organic matter (SOM) and the abundant diversity of plant roots.

Soil Organic Matter

SOM is essential to soil health as it imparts beneficial chemical, physical and biological properties. It is critical for increasing the soil’s cation exchange capacity, a product of carbon content. SOM also benefits the physical properties of soil by building soil structure and increasing water-holding capacity.

SOM also supports microbial activities, including mineralizing nutrients, developing mycorrhizal relationships with crop roots, and producing sticky substances that hold soil aggregates together.

The second main contributor to soil health is the abundance and diversity of plant roots. Each plant family has unique endophytes (organisms living in plant cells) introduced via the seeds. Active mainly in the rhizosphere (root zone), these organisms are essential to plant health and resilience.

Spring Cover Crops

Early spring cover crops protect the soil, add organic matter and suppress weeds. Legumes mixed with oats or barley can act as nurse crops to outcompete weeds while establishing legumes. Yellow mustard is a great source of organic matter and can also suppress soilborne diseases and weeds. Annual ryegrass has the same weed suppression abilities and can be sown as soon as the ground is workable in early spring.

Garden Maintenance Jobs for May

A teepee in a lush garden. Part of the maintenance jobs to do in May includes preparing structures for vining plants
May Garden Maintenance Jobs to Do

Plant out Seedlings

With the last frost past (hopefully), we can finally start moving seedlings into their final growing spaces. However, it is essential not to move them right out. If you were to do that, the seedlings would struggle and possibly die from transplant shock.

It is essential to introduce these seedlings to the outside world gradually. While they have been in your greenhouse or polytunnel, they were protected from the harshness outside – moving them out into a vastly different environment will cause unmanageable stress.

Hardening off involves gradual exposure of the plants to more extreme conditions — helping them toughen up. Harding off can include limited exposure to cold and drought, followed by a return to coziness. Incrementally expose the plant to differing temperatures, brighter light, and less water, gradually building resilience.

This process should be done over 7 to 10 days allowing the plant to be left out permanently eventually. Hardening off prevents plants from the shock of immediate exposure to more stress, preventing setbacks or even death.

Keep Sowing Seeds

Sowing seed continues this month as we can start direct sowing seed; this will save compost and time potting and is a great way to fill up beds that have yet to be allocated.

By moving all your seedlings out into their final growing spaces, you get space available, allowing you to continue growing starter plants. Carrots and parsnips can be sown in situ in their bed this month.

Clear Away Rubbish and Decaying Matter

Our focus on keeping up with all the sowing and planting required this month can result in the garden getting into a mess. All this rubbish is an ideal location for slugs and snails to hide. These can cause loss as you discover all your newly planted seedlings have been cut off at their feet. Clearing up this mess in the garden will reduce the hiding places for this pest.

Erect Plant Supports

May is the last month to get out plant supports and structures. We often need to remember these when required and then scramble to build them when planting.

Erect support structures for the following plants:

  • Beans
  • Peas
  • Gourds
  • Sweet pea
  • Honeysuckle
  • Clematis
  • Roses
  • Ivy

Protect Seedlings from Bad Weather

Even though May is getting warmer, bad weather can still affect your tender young plants. Meshing and fleecing them this month can help to keep them cozy when nighttime temperatures fall.

There are many ways to protect young seedlings, like using fleece, mesh, plastic tunnels, bottles, and greenhouses, to name a few. Be mindful of allowing plenty of airflows as daytime can also get very hot in May.

Keep An Eye Out for Pests

With the days lengthening and the weather warming, this month brings on the onslaught of pest species moving into the garden. It is vital to remove the habitat for these pests.

Managing pests may require removing built-up rubbish, bricks, and rotting wood. Some of the pests you will see this month include:

Slug & SnailsWoolly Aphid
Vine WeevilTortrix Moths
Fuchsia Gall MiteBox Tree Moth
Glasshouse ThripsRosemary Beetle Larvae
Viburnum BeetleAnts

Keep The Weeds Under Control

The increase in the temperatures and light levels boosts growth, including weeds. Ten minutes of work done on time will save you days of work in later months. Hoeing off young seedlings as they germinate is easy work and prevents weeds from growing and taking up valuable water and nutrients otherwise intended for your young plants.

Soil Health Tasks for May

Make your own compost:

  • Buy a compost unit or build one from recycled wood pallets, concrete blocks, sturdy wire, etc. The minimum size should be a cubic yard or meter.
  • Make successive, 4-inch-thick layers of plant waste, alternating between green and brown materials – nitrogen and carbon.
  • Animal (not pet) manure, finished compost, blood meal, or nitrogen can be added to each layer if desired.
  • Keep the pile 50% moist – a single drop is visible when tightly squeezed in your fist.
  • Ensure the pile gets oxygen throughout – at least 6%. Do this by regularly turning the pile – every four days initially and then less as the pile matures. When to turn is indicated by temperatures at the core of the pile.
  • Compost should be ready to use in two to twelve months, depending on how intensely it is managed (kept moist, turned, etc.).
  • Cover it with an old rug or tarpaulin to prevent rain from draining nutrients from the pile.

Vegetable Gardening Jobs to Do in May

A garden filled to abundance of vegetables. May vegetable gardening jobs includes getting crops into the ground and harvesting short season crops like lettuce.
May Vegetable Gardening Jobs to Do

Vegetable Garden Tasks for May

As already discussed, sowing continues during May, and the following list is what vegetables you should be considering sowing this month.

Vegetable Planting Guide – May

It’s time to start hardening off your frost-tender plants, including vegetables and herbs that were started indoors. You can also sow seeds outdoors for beans, okra, pumpkin, sweet corn, and watermelon. Plant only partial rows for beans and sweet corn so that successive plantings can be done every week or two. Sweet corn should be planted in paired rows or blocks for optimal pollination.

By the beginning of this month, it should be safe to plant almost everything outdoors, including tender annual flowers like impatiens, tomatoes, peppers, and eggplants. Lastly, wait for the soil to warm up before planting sweet potato slips.

To get rid of Colorado potato beetles, manually remove them by hand or use an organic insecticide called Spinosad if the infestation is severe. These beetles have yellow and black stripes as adults, while their eggs are yellow and laid in clusters on the undersides of leaves. The red humpbacked larvae are usually found on the stem tips and can be present throughout the season.

Be on the lookout for Striped and Spotted Cucumber Beetles that can spread bacterial wilt to your squashes and melons. Throughout the season, you can manually remove both adults and eggs.

Another pest to watch out for is the Mexican Bean Beetle. As a precaution, cover your entire crop with a floating row cover as soon as your seedlings emerge.

During warm weather, aphids can be found on various host plants. Check for them on recently opened leaves and look for sticky leaves, as this is a sign of their presence due to the secretion of “honeydew.”

To remove most of them, spray the leaves with a strong water jet. For organic-approved control, insecticidal soap works well if the insects are thoroughly wetted. A second and third treatment within 5 to 7 days may be necessary to kill newly hatched eggs.

As the summer season approaches, taking precautions against pests and ensuring a healthy growth for your plants is important.

Keep an eye out for the squash vine borer, a 1-inch-long moth with orange and green coloring, which lays brown eggs at the base of squash vines. Remove any eggs by hand or wrap the lower 6-12 inches of stem with aluminum foil or row cover to prevent larvae from burrowing into the stems.

Cutworms can also be a problem for newly transplanted vegetable plants – protect them by making collars out of two-inch wide strips of cardboard. Place the collars around the plants, pressing them about one inch into the soil to keep the cutworms out.

Remember to keep up with hilling your potatoes and pinch herbs like basil, mint, oregano, and savory to encourage bushy growth. Regularly harvesting leafy greens is important, as they can bolt quickly.

Ensure a trellis system is in place for your tomato patch before the plants sprawl. And if you’re looking to start new plants, consider taking softwood cuttings of shrubs like spirea, lilac, and viburnum in mid to late May.

Earth Up Potatoes

Most areas’ last frost will be later this month. It is essential not to fall into a false sense of security with the warm days we are experiencing. Frost can still be a real threat, and it is vital to ensure that we protect our potato plants from this risk.

If you grow your potatoes with the old-fashioned trench methods, you must earth them up as they push through the surface. I prefer growing potatoes in containers, which gives me many advantages over ground-grown potatoes. Not only can they be filled at planting time, but they can also remain in the polytunnel or greenhouse until after the risk of frost has passed.

Fruit Garden Jobs to Do in May

Ripening peaches on a branch. May fruit gardening jobs to do include weed control to minimize pests.
May Fruit Gardening Jobs to Do

Investing in a fruit cage or netting is important to protect your crops from birds. While a fruit cage may be a significant investment, it is highly effective.

If you’ve planted strawberries this year, removing the flowers is recommended so they do not produce fruit in the first year. This will allow them to focus on strengthening themselves for future years, resulting in better performance.

When tending to your garden, make sure to remove all the weeds. However, you must remove their roots for perennial weeds like dandelion and dock to prevent re-growth. Bindweed can be especially challenging to eradicate since even a small piece of root can regrow. The most effective way to deal with it is to use a glyphosate-based weedkiller, which can penetrate the roots and kill the plant. However, there are some concerns over the safety of glyphosate.

Another weed that tends to resurface at this time of year is Horsetail (Equisetum Arvense). To eliminate it, you must apply a translocating weedkiller multiple times, rendering the plot unusable for some time. Organic growers can keep hoeing and removing roots, which is laborious and time-consuming.

If you have used a product like ‘Weed and Feed’ on your lawn, be aware that the lawn trimmings may harm your crops. Check the manufacturer’s instructions carefully before composting.

Indoor and Container Gardening Projects for May Month

A pink Iris as part of getting bulbs planted in containers using the lasagna layering method
May Indoor and Container Gardening Projects

Fertilize indoor plants every fortnight using a diluted balanced fertilizer. Using a highly diluted fertilizer more often than occasional fertilizing using a concentrated mix is better.

Repot houseplants that need it. An indicator that your plant needs repotting is if it needs less water more often, meaning the put is mostly comprised of roots. Always repot to a pot only one size up. Most houseplants prefer to be root-bound to some extent.

Plant a Bulb Lasagna

Planting bulbs in layers, also known as “bulb lasagna,” may sound peculiar, but it results in a stunning display of abundant flowers. The process involves planting bulbs in layers, which will bloom together or one after the other come spring. This planting technique suits any outdoor space, whether a vast lawn or a small balcony.

When selecting flowers for your garden, it is recommended to choose early bloomers like Crocus and spring bloomers like Daffodils for longer-lasting results. If you decide to plant Daffodils, consider selecting a dwarf variety, as they will thrive better in smaller spaces.

To achieve a professionally landscaped look where all your bulbs bloom simultaneously, consider planting taller species like Tulips with smaller ones like Anemones. This combination creates a beautiful verticality.

Space your bulbs their width apart and three times their height deep.

What You’ll Need to Create a Bulb Lasagna

You can choose two or three varieties of your preferred flower bulbs. They can either have the same flowering period or different ones. If you want flowers from winter to the end of spring, it’s best to pick different flowering periods. You will also need a large pot with holes at the bottom to avoid excess water accumulation. Moreover, you will need enough soil to fill the container. We suggest using two parts loam-based soil and one part gravel, as the gravel will enhance the drainage.

Creating a Bulb Lasagne

To properly plant bulbs in a pot, plant the taller ones about a third of the way down and cover them with soil. When planting the second layer, ensure they are not directly above any bulbs in the first layer to avoid growth interference. If planting three layers, repeat this step once more before filling the pot to the top with soil. Finally, give the pot a good watering.

Once you notice foliage sprouting from the soil, it’s time to increase watering frequency. Try to maintain consistently moist soil. Additionally, you can give your plants a liquid feed every two weeks, such as diluted tomato food, to promote healthy growth and prevent excessive foliage growth at the expense of flowers.

When your plants stop flowering, and their leaves start turning brown, it’s time to move them to a sheltered area and reduce watering to a bare minimum.

Ornamental Garden Jobs to Do in May

A purple Canna, an ideal bulb flower to plant in May.
May Ornamental Garden Jobs to Do

Flower Garden Planting

Listed below are flowers that can be planted in May.

Botanical NameCommon Name
AgastacheGiant Hyssop
California PoppiesCalifornia Poppies
CelosiaCock’s Comb
CleomeSpider Flower
ColumbineGranny’s Bonnet
CosmidiumCosmidium Daisy
CynoglossumHound’s Tongue
EchinaceaCone Flower
GaillardiaBlanket Flower
GauraButterfly Bush
GilliaFringe Cups
GypsophilaBaby’s Breath
LavateraTree Mallow
Morning GloryMorning Glory
NemophilaBaby Blue Eyes
OenotheraEvening Primrose
PhaceliaScorpion weed
PhysalisChinese Lantern
RatibidaMexican Hat
ScabiosaPincushion Flower
StaticeSea Lavender
Sweet PeasSweet Peas
TithoniaMexican Sunflower
Flowers That Can be Planted in May

Plant Bulbs for Spring Flowering

It’s recommended to plant your bulbs as soon as they arrive at your doorstep. However, if that’s impossible, you can store them in a dry and dark place for a few days. Certain species, such as Tulips and Alliums, can last even longer. For summer-flowering bulbs, the ideal period for planting is between March and June. It’s best to plant them earlier in the season since if you grow them just before July, they’ll bloom in late summer.

Preparing your Bulb Garden

To ensure successful bulb planting, it’s important to have moist and well-drained soil. Bulbs thrive in loamy soil, which consists of equal parts sand and silt, with a touch of clay. Add a layer of organic matter two inches thick to your soil every autumn to achieve this type of soil. Come springtime, blend it into the top seven inches of soil. If you prefer to plant bulbs in pots, a great option is a soil, two parts loam and one part gravel.

Positioning your Bulbs

When planting bulbs, it’s important to ensure that the pointed tip faces upwards. When handling smaller bulbs like Grape Hyacinths, be gentle to avoid pushing them over. Begonias don’t have a sharp point, but you can usually spot the tip on the concave side. A species’ natural habitat can give you an idea of where it will grow best.

For example, Snowdrops, which bloom in late winter, thrive in cold weather and should be planted in cold pockets. Bluebells, conversely, are forest dwellers and prefer dappled shade, so planting them beneath deciduous trees will help them flourish.

Summer and Autumn Bulbs

The list below covers bulbs best planted between March and June.

BulbPlant DepthSpacingSite Preference
Tulip4 inches (10cm)4 inches (10cm)Sunny with well-drained soil
Daffodil4 inches (10cm)4 inches (10cm)Sun or part shade
Grape Hyacinth4 inches (10cm)2 inches (5cm)Sun or part shade
Winter Aconite2 inches (5cm)2 inches (5cm)Sun or part shade
Bluebell4 inches (10cm)4 inches (10cm)Sun or part shade
Snowdrop4 inches (10cm)2 inches (5cm)Part or dappled shade
Ranunculus2 inches (5cm)4 inches (10cm)Sun
Crocus3 inches (75mm)2 inches (5cm)Open and sunny
Hyacinth4 inches (10cm)4 inches (10cm)Sunny with well-drained soil
Iris4 inches (10cm)6 inches (15cm)Sunny with well-drained soil
Allium (Large)8 inches (20cm)6 inches (15cm)Full sun
Allium (Small)4 inches (10cm)2 inches (5cm)Full sun
Anemone2 inches (5cm)2 inches (5cm)Full sun or part shade
Ipheion uniflorum4 inches (10cm)2 inches (5cm)Sunny and sheltered
Ornithogalum nutans3 inches (75mm)4 inches (10cm)Sunny with well-drained soil
Puschkinia libanotica4 inches (10cm)2 inches (5cm)Sun or part shade with well-drained soil
Flower Bulbs for Early Spring Planting

May Lawn Care Jobs

In the preceding three months, you’ve set the stage for a healthy lawn that should now be thriving, needing a trim every five days or so. Now that your lawn is more robust, it can handle spot treatment of broadleaf weed killers. Do this on a day that won’t cause the poison to be blown across the property – choose a fine, still, and dry day.

Cut the grass at the specified heights and leave the clippings on the lawn. Clippings enrich the soil and add nutrients.

Use post-emergent herbicides to spot-treat difficult weeds. When weeds are tiny and actively developing, treatment is most effective. Fertilize lawns as needed based on soil test results.

May Gardeners’ Focus

A low shot of yellow tulips as we focus on getting bulbs planted for a fall floral show.
May Focus Jobs to Do

Keep up with the tasks of sowing and planting for this month. Summer is approaching, and we can enjoy all our hard work.

Sticking to our theme of minimizing soil exposure this year, our garden preparation jobs included getting cover crops in the ground. Having roots in the ground for most of the year ensures that soil biology is optimized, allowing the little miracle workers to improve soil aeration and nutrient availability.

I added many garden maintenance tasks for you to select from. One that can’t be ignored is garden hygiene, which is essential in minimizing other risks.

Vegetable gardening jobs in May are again focused on getting produce in the ground. You’re already harvesting lettuce and other short-growth crops.

Fruit garden jobs for May, regrettably, included using glyphosate-based weedkiller. Select a product labelled to control the targeted weeds and follow the label, including the use of personal protective equipment.  

This month’s indoor and container gardening projects included bulbs for late summer bloom. Bulbs are always worth the investment, but getting them in soil soon after your mail order arrives is important. Autumn bulbs were also the topic of our ornamental garden jobs to do.


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