For years, Teddy Bair gardened on a grand scale, tending multiple garden "rooms" and a koi pond at his Tudor house in Minneapolis.

For years, Teddy Bair gardened on a grand scale, tending multiple garden “rooms” and a koi pond at his Tudor house in Minneapolis.

When he decided to move to a condo, his friends asked: “What are you going to do when you give up that garden?”

“Get a bike and ride around to see what everyone else has been doing for 20 years,” he told them.

Bair gave up his big garden but not gardening. He has scaled back and is growing plants on a balcony with a sweeping view of the downtown skyline.

“I get great comfort out of it,” he said of his garden filled with coleus, banana trees and other tropical plants. “I really don’t miss it (his former garden). I love living here. Life is so much easier.”

Many longtime gardeners are making the same transition, trading big earthen plots for patio pots. Urban migration, the downtown condo boom and a wave of retiring baby boomers have combined to boost the number of balcony and rooftop gardens.

Balconies pose particular gardening challenges.

“There’s a different set of rules to follow,” said Scott Endres, owner of Tangletown Gardens in Minneapolis. “You can have almost as much diversity as on the ground. It’s all about site conditions.”

Here are important considerations for balcony gardening.

• Size and scale. Your garden space might be small, but that doesn’t mean you should stick to small plants, Endres said.

Bigger, bolder plants can hold their own, especially if you live downtown with big buildings and urban noise.

“Choose things that can compete with the scale of the surroundings,” he said.

• Tougher plants. Your favorite garden flower might not be sturdy enough for balcony conditions, which are often windy and hot.

Endres suggests plants with tougher, fleshier leaves such as mother-in-law tongue and succulents. Plants with big loose leaves, such as banana trees, could be shredded by wind.

• Good-quality soil. Plants have less soil in containers than in the ground, so the character of the soil is more important. Good soil will help provide nutrients.

Soil that contains water-holding polymers can help plants weather the hot, dry conditions on many balconies.

• Edibles. If you want to grow tomatoes on a balcony, they’ll need lots of water and attention. You might want to set up drip irrigation to ease watering.

When choosing containers for vegetables, get the biggest ones you can fit into your space. Herbs such as basil and mint are also good balcony crops. They’re easy to grow, expensive to buy at the grocery store, and they come in handy for summer favorites such as mojitos or homemade pesto.