How to make a rooftop garden

City living doesn’t immediately lend itself to a traditional gardening opportunity like digging up a corner of the grass in your large backyard and turning it into a garden plot. But, while all gardens need to be rooted, there is no requirement they need to be on the ground. You can make a garden on your balcony, terrace, or rooftop.

Rooftop gardens are an excellent solution for those that live in an urban area with limited outdoor space and/or in an apartment that doesn’t include any at all. If you are such a person and want to make your own rooftop garden there are a few things to take into consideration during the planning process.

First, confirm with a structural engineer that your roof has the load capacity to support a garden. At the same time, make sure your building roof is up to city codes for installing a garden and becoming a living space. For instance, structures in New York City must have specified rails or guards installed around the roof’s perimeter. Also, make sure to consult with your landlord if you rent or your management company or co-op board if you own.

Once you have all of the permissions and approvals confirmed, take a good look around your roof space.

How to make a rooftop garden

Monitor for both sun exposure and wind exposure for a couple of weeks. A garden will need six to eight hours of sunlight a day. Roofs will experience higher winds than the ground so consider a wind-breaking apparatus such as a trellis or even pieces of wood with decorative cutouts. Don’t use anything completely solid as it’s likely to just get knocked over by the wind.

AMAGABELI GARDEN & HOME

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Next, figure out how you’re going to get water up to your garden. If possible, have some kind of water storage or automatic watering system built. Most large rooftop gardens have a drip irrigation system fed from installed spigots. If your roof is able to handle the weight, consider rain barrels that will collect and store water on your roof. Remember that wind will dry out plants quicker so you’ll likely need to water more frequently. If you do end up having to cart water up from floors below, look at the activity as a good weight training workout. (I live on the 5th floor of a walkup so I implement this mindset often).

Growing plants on your rooftop requires building large container beds or using multiple smaller containers for single plants. Consider lighter-weight materials like plastic or other synthetics for large beds. If, though, you plan to grow a potentially top-heavy plant like a small tree or tomatoes (with heavy fruit) a heavier pot will prevent them from toppling over.

Heavier clay and terra cotta pots will also heat up and retain that heat longer in the sun which will mean you’ll need to water even more frequently. Another option is fiberglass plant containers which are quite popular among rooftop gardeners.

Lightweight Concrete Modern Long Low Outdoor


You’ll also need to cart soil up to your roof. A lightweight potting and gardening mixture is ideal:

Moisture Control 25 qt. Potting Soil Mix

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Now that you’ve planned out your space, the next step is to choose what to plant in your rooftop garden.


Best Plants for your Rooftop Garden

Honestly, you can grow almost anything in a container on a roof except for very tall trees (because of lack of root space and the top-heavy problem). Herbs, vegetables, and perennial flowers that don’t develop extensive root systems are all well suited for rooftop gardening. Small trees and shrubs work in large containers, as do ornamental grasses.

Choose plants that are drought and heat tolerant. They’ll have a better chance of flourishing on your hot, windy roof. So will plants that are native to your area.

Below are some popular plants for rooftop gardens and green roof spaces.

Ornamental Grasses

300 Blue Fescue, Ornamental Grass Seeds - Festuca Glauca - Perennial


Blue fescue is a drought-tolerant grass that requires little care save for a good layer of mulch on top of the soil where it’s planted. And the blue leaves and yellow flowers will add color to your garden beds.

Ornamental trees and shrubs

2.5 Qt. Blue Star Juniper Shrub with Low-Growing Mounded Icy Foliage


Blue Star Junipers are small, evergreen shrubs that mature to two to three feet tall with a similar spread. They are drought tolerant and grow in a mound shape with silvery blue leaves.

Another small tree, the Dwarf Japanese Maple will grow to between three and five feet in large containers and add a little shade to your outdoor space.

Ajuga

Mahogany Ajuga - Carpet Bugle - 48 Plants - 1 3/4


Ajuga, also called bugleweed, is a fast-growing, creeping evergreen plant with dark leaves and blue, violet, or purple flower spikes. Bugleweed acts as an aggressive ground cover in areas where other plants are difficult to grow. They also develop an extensive root system that helps to discourage weeds from taking root. Plant as ground cover at the bottom of your small trees or fill in space in large containers.

Hostas

Breck's® Many Shades of Hosta Collection


There are over 2,500 varieties of hosta plants. Their lush leaves come in a variety of greens; from an intense dark, blue-green to a light chartreuse to a green-tinted cream. Once established, these shade-loving plants will persevere through drought and questionable soil mixtures.

Astilbe Fanal

Red Fanal Astilbe


While they do require frequent watering, astilbe fanal is a shade-loving plant that will provide your garden with some vibrant color. They’ll also attract hummingbirds and bees, both of which are important in sustaining ecosystems.

Lavender

1400 English Lavender Seeds for Planting Indoors or Outdoors


Lavender is an extremely drought-resistant plant once established making them a great choice for a rooftop. They’ll also come back every year and the English variety is quite hardy in the cold.