Spring Balcony Garden Checklist: Getting Ready to Plant

The first mild weekend of the year makes it tempting to buy a tray of plants and start filling pots. A spring balcony garden gets off to a better start if you do a few less exciting jobs first, in an order that saves you from doing any of them twice.

This checklist runs from cleaning to planting. Most of it fits into one or two unhurried afternoons, and the early steps can be done while it is still too cold to plant anything.

The checklist at a glance

1. Clean up

Start with a clear floor. Sweep up fallen leaves, old potting mix and winter grit, and move the pots so you can reach the corners.

• Clear the floor drain or scupper so spring rain and watering runoff can leave the balcony.
• Empty pots of last year’s dead annuals and shake out old roots.
• Wash pots and saucers with warm soapy water and a stiff brush, then rinse and let them dry.

2. Inspect containers, stands and fixings

Winter is hard on equipment. Look over each container for frost cracks, especially terracotta and thin ceramic, and check that the drainage holes are open. Rock every plant stand and shelf to feel for wobble, loose screws or rust.

Then examine every hook, bracket, chain and railing planter fixing before you refill anything it holds. Look for rust, bent metal, cracked plastic, frayed hangers and worn straps. Replace anything doubtful rather than trusting it for another season.

If the layout felt cramped or awkward last year, this is the moment to rethink it while the pots are empty. The guide to organizing a balcony garden has ideas for shelving, storage and keeping a clear path.

3. Check what survived

Do not rush to throw out plants that look dead. Many perennials and shrubs in pots leaf out later than the same plants in the ground, and some stay bare well into spring.

• Scratch test. On woody stems, scrape a small patch of bark with a fingernail. Green and moist underneath suggests the stem is alive; brown and dry suggests that section has died. Test lower down before you decide.
• Look at the base. Herbaceous perennials often send up new shoots from the crown at soil level.
• Wait. Give doubtful plants several more weeks of mild weather before you give up on them.

4. Refresh the potting mix

Potting mix breaks down over a season. It settles, drains more slowly and holds few nutrients by the following spring.

For annual flowers and vegetables, replacing the mix gives the most reliable start, particularly if last year’s plants had disease problems. In large containers, many gardeners remove the top third or so along with old roots and top up with fresh mix. For perennials staying in their pots, scrape away the loose top layer and replace it.

If you are buying a new bag, the guide to potting soil for containers explains what to look for on the label.

5. Get the timing right

Timing depends on where you live, so no single date works for everyone. Two groups of plants behave very differently.

Cool-season plants can start early

Lettuce, peas, parsley, pansies and violas tolerate cool weather and light frost, so they can go out well before summer plants. They are a good way to have something growing while you wait. See growing lettuce in containers for an easy first crop.

Frost-tender plants must wait

Tomatoes, peppers, basil and most summer annuals are damaged by frost and sulk in cold potting mix. Plant them outside only after the danger of frost has passed in your area. Your local extension service or weather service can tell you the average last frost date for your location; treat it as an average, not a promise, and watch the forecast.

For perennials and shrubs, look up your zone on the USDA Plant Hardiness Zone Map and compare it with the plant tag.

Harden off plants raised indoors

Seedlings and plants that have lived indoors or in a greenhouse need a gradual introduction to wind, direct sun and cool nights. This is called hardening off.

1. Set them outside in a sheltered, shaded spot for a couple of hours.
2. Over about a week, lengthen the time and move them gradually into more sun.
3. Bring them in if frost or strong wind is forecast.

6. Re-check the sun and plan your planting

The sun is higher and follows a different path than it did in autumn. A corner that was shaded all winter may now receive several hours of direct light, and nearby trees coming into leaf can do the opposite.

On a clear day, note which parts of the balcony are in direct sun every hour or two. As a rough guide, full sun means about six hours or more of direct sun, and shade means less than about three. Choose plants to match what you observe now.

Then write a list before you shop: how many containers you have, their sizes, the light each spot receives and what you want in each. A list keeps you from coming home with more plants than pots. If this is your first season, balcony gardening for beginners walks through those choices step by step.

7. Start feeding as growth begins

Hold off on fertilizer until plants are actively growing. Check whether your fresh potting mix already contains fertilizer, and if it does, wait until that supply runs down.

When you do begin, follow the product label for rate and timing, and never use more.