March is the first month of Spring and the last month of Winter, often shifting between these two seasons at the drop of a hat. As new life emerges from the ground, this is a great time to do some serious planting while buttoning up those winter gardening tasks. The forward momentum is unstoppable, and the work done in the garden now will set the stage for the coming season.
March To Do List in the Garden
Seasonal Color
Container plantings that may have been neglected or filled with holiday décor are primed for a reset. Refresh containers with a vibrant early Spring display using fragrant Wallflower and Hyacinths, beautiful Ranunculus, flouncy Anemones, and vivid Spring flowering bulbs.
Spruce up vacant landscape beds with early annual color like Primroses, Pansies, and Violas. Hellebores are the perfect perennial plant investment—they are evergreen, easy to care for, and in bloom before other plants wake up in the garden.
Planting & Maintenance
Apply G&B Fertilizers as new growth appears on perennials and shrubs to help support lush, vigorous growth, and be sure to protect perennials from slugs with Sluggo or Slug Magic.
Once they have put on two inches of fresh new growth, fertilize roses with Portland Rose Society Fertilizer 15-10-10 or Portland Rose Society Organic Fertilizer 5-4-4.
Divide Hostas, Irises, and Daylilies as they emerge by digging up the entire plant from the garden beds and using a shovel or hori hori knife to cut them into smaller clumps. Replant the pieces back in your bed, and share any extras with friends.
Relocate perennials and Roses while they are emerging from dormancy—now is the perfect time to dig up and transplant them without interrupting their growth or diminishing their potential for the upcoming season.
Prune:
- Prune spring-flowering shrubs like Camellias and Daphne after blossoms fade.
- March is the time to prune evergreen plants like Abelia, Pine, Ferns, Pyracantha, Lavender, Rockrose, Aucuba, and Box Honeysuckle.
- Deciduous plants like Mimosa, Spiraea (summer-blooming), Twig Dogwood, Witchhazel, Beautyberry, and Caryopteris can also be pruned in March.
- Make sure ornamental grasses have all been cut back at the beginning of the month, as pruning too late in the Spring will damage the growing tips of their blades.
Use Moss Out for roofs and walkways to clear moss around the home. This non-staining formula will kill moss without discoloring concrete.
Edible Gardening
In March, the best use of time and money in the vegetable garden is to invest in your soil.
- Use a soil testing kit to measure the nitrogen, phosphorus, potassium, and pH levels of soil to plan for its needs for the coming growing season.
- Amend the soil with G&B Soil Building Conditioner, G&B Harvest Supreme, or Malibu Compost to enrich soils and improve quality.
- Plow or turn in cover crops now and wait a few weeks before planting new crops.
- Use a soil thermometer to check temperatures; it’s okay to start planting cool-season crops at 40-45 degrees (Fahrenheit).
Plant starts of cold-season crops like broccoli, cabbage, cauliflower, kale, leeks, lettuce, onions (from seed or from sets), peas (snow, shelling, snap), radishes, spinach, and Swiss chard. Buy seed potatoes and chit them in a cool, dark place to form growing eyes until soils reach 45-50°F when they can be planted outdoors.
Plant perennial vegetables like artichokes, asparagus, and rhubarb to get a healthy vigorous root system started for the coming growing season.
Protect tender shoots of vegetables from slugs with Sluggo or Slug Magic.
Plant sturdy perennial herbs like chives, lavender, rosemary, sage, and thyme.
Start tender crops like tomatoes, peppers, squash, and eggplant from seed indoors.
March is the perfect time to plant fruit trees and berries, and by adding an additional fruit or berry of a different variety, you can often dramatically increase yields!
Feed raspberries and other cane berries with a slow release, organic fertilizer such as G&B Citrus & Fruit Tree Fertilizer.
March Lawn Care
Work done to the lawn in March help sets the stage for the coming season. By removing moss, fertilizing, and reseeding now, you’ll help ensure a lush lawn for the summer.
Apply Lilly Miller Moss Out or Bonide MossMax to control moss in lawns.
Add lime to adjust pH and make the soil less acidic, which allows fertilizer to be more easily taken up by the grass and makes acid-loving moss uncomfortable (do a pH test if unsure).
Apply G&B Lawn Fertilizer after the first mowing of the season to support a lush carpet of grass. After March 15th, put down grass seed to patch and fill areas. Cover new seed with a fine layer of G&B Soil Building Conditioner (3 cubic feet covers 144 square feet at ¼-inch thick).
Consider professional lawn renovations like aeration and overseeding with our Residential Landscaping Department.
Organizing the Garden Shed
Go through old chemicals and fertilizers. Properly dispose of anything that is old or ineffective. Many waste companies have specific days when residential chemicals can be disposed of during weekly pickup or at their facility. Check with your local waste management company for details or call Oregon Metro at 503-234-3000. Make a list of chemicals and fertilizers that are commonly used and need to be replenished.
Go through old seeds and dispose of those that are too old to germinate (many seeds have an expiration date on their package). Generally speaking, the lifespan is:
- 1-2 years for large seeded plants like corn, beans, and squash
- up to 5 years for small seeded plants like lettuce, leeks, and grass seed
Indoor Gardening in March
March is the start of the active growing season for houseplants, so it is now time to give them a little extra care.
Freshen up your indoor plants with a topdressing of worm castings—scratch the soil with a fork and add the worm castings and fresh potting soil.
If needed, repot your houseplants:
- Remove the old soil, taking care not to damage the roots, and replant the plant in a slightly larger container with fresh soil.
- Once repotted, take caution not to overwater your houseplants—the roots will not have filled the larger volume of soil and are therefore more prone to suffocation in overly wet soils.
Do some basic plant maintenance by cleaning off their leaves with mild soapy water or neem oil, and clean the outsides of containers and drainage saucers.
Take cuttings from vigorous, healthy plants and share them with friends once they have rooted!
What to Do for Fun in March
Near the end of the month, sow some grass seed to grow indoors for Easter decorations; young grass shoots should be up within a week or so.
Make a Spring bulb dish garden by using potted bulbs, sheet moss, and soil in a low bowl to create a miniature landscape and brighten up any spot in your home!
Feed the birds! Even though the garden is showing signs of active growth, March is the most challenging month for our feathered friends. With virtually no seeds or berries left over from fall and winter and no new seed heads expected for a few more months, Spring is a critical time to support wildlife in the garden by supplementing their diet with birdseed. Clean your birdfeeder weekly and don’t allow it to go empty—once you start feeding birds, it’s important not to stop!
View our garden tips and checklist for April in the Garden. Or go back and see our garden tips and checklist for February in the Garden.