Growing plants on a balcony with little room

A small balcony can support a surprisingly productive mix of plants when you plan around four things: sun exposure, wind, weight and watering. The direction the balcony faces decides how much direct light reaches the containers, while the height of the building and any nearby walls shape how strong the wind is. Settle those basics first, and the choice of containers and plants becomes much simpler.

Start by watching the balcony for a day. Note when the sun first reaches it, when it leaves and whether any part stays shaded. Full sun generally means at least six hours of direct light, while part sun usually means three to six hours. In the Northern Hemisphere, a south-facing balcony usually receives the most sun and a north-facing one the least, and the pattern reverses in the Southern Hemisphere. Flowering plants and most herbs want full sun, while leafy greens and ferns cope with less.

Checking the weight limit

Containers add up quickly. A large pot filled with wet potting mix can weigh many pounds, and several of them on one balcony add real load. Ask your building manager or a structural professional about the balcony's rated load before filling a row of containers, especially on older or enclosed balconies. Lightweight containers made of plastic, resin or fiberglass help, and so does lightweight potting mix in place of garden soil, which compacts and holds far more water. Spread the heavy pots out instead of grouping them in one corner. Wet soil is the main reason containers overload a balcony, because a pot that feels manageable when empty can become very heavy after watering. Plan for the weight of each container when it is full and soaked, not when it is empty.

Handling wind and exposure

Wind is often the hidden problem on a balcony. It dries soil and leaves quickly and can snap tall stems or shred broad foliage. Place taller or top-heavy plants in the most sheltered spot, group containers so they shelter one another, and choose compact or sturdy varieties where gusts are strong. A windbreak of lattice or mesh softens the wind, but a solid screen can create swirling air on its far side that knocks pots over, so a porous barrier usually works better. Secure lightweight containers with a tie or clip, especially on higher floors.

Wind also draws water out of leaves and soil faster than calm air does, so a sunny, windy balcony may need watering even when the morning seemed fine. Check pots in the afternoon as well as the morning during hot spells.

Watering and feeding in containers

Container plants depend entirely on you for water, and small pots dry out quickly on a sunny, windy balcony. In summer, you may need to check every day. Push a finger into the mix, and water when the top inch or two feels dry. Water until it runs from the drainage holes, then empty any saucer shortly afterward so the roots do not sit in water. Hanging baskets and wall pockets dry fastest, so they need the most frequent checks. Frequent watering also washes nutrients out of the mix, so feed container plants during the growing season at the strength listed on the product label.

If a container has dried so much that the soil pulls away from its sides, water runs straight down the gap and out the bottom. Stand the pot in a bucket of water until the bubbles stop rising, then let it drain before returning it to its place.

Railings, edges and safety

Railing planters free up floor space, but they need care. Use brackets rated for the planter and its wet weight, fix them firmly, and keep containers from leaning out past the railing, where a gust could topple them onto people below. Keep heavy pots well back from the edge, and use trays or saucers so drainage does not spill onto neighboring balconies. A pot that is safe on a calm day can still shift in a storm, so anchor or weight the heaviest containers where they cannot slide. Check your building's rules before hanging anything outside, because some buildings restrict railing planters. Inspect brackets and hooks at the start of each season for rust, loose screws or cracks in the railing, and replace any fixing that shows wear.

Choosing plants that suit a balcony

Plants that tolerate containers, wind and changing water needs make the best balcony companions. Compact herbs such as thyme, parsley and chives, dwarf or bush tomatoes and peppers, and flowers such as marigolds and geraniums are common choices. Check the mature size on the label before you buy, because a plant that looks right in spring can outgrow its pot by late summer. Group plants by how much water they need, so thirsty ones sit together and drought-tolerant ones sit apart.

Leafy greens such as lettuce and chard tolerate partial shade, which helps on a balcony that gets only a few hours of direct sun. Harvesting the outer leaves while the plant keeps growing from the center, often called cut-and-come-again harvesting, keeps these plants compact and productive in a pot. Treat the balcony as a set of small microclimates, and add more containers only after you have seen how the first ones handle a full season.