Rooftop Container Vegetable Gardening: How To Grow An Urban Garden

How does rooftop container vegetable gardening transform unused spaces into mini edible farms?

If it interests you, let’s dive in!

FTC Disclosure

Why would you want to grow edibles on your roof?

  1. Save space especially if you’re living in a small apartment
  2. Reduce the ecological footprint of city buildings.
  3. Keep buildings quieter inside.
  4. Keep your home cooler in summer and warmer in winter through shade and natural insulation.
  5. Save energy costs on air conditioner and heater and cut down emissions.
  6. Reduce rainwater run-off to prevent flooding.
  7. Improve air quality as the crops release oxygen.
  8. Protect threatened biodiversity and wildlife.

I hope these 8 reasons are enough to motivate you to grow vegetables and herbs in containers on the roof.

If you don’t have the gardening space to grow your own food, look up! In urban and suburban areas across the country, homeowners are starting rooftop vegetable gardening in residential and commercial buildings.
The Rooftop Growing Guide: How to Transform Your Roof into a Vegetable Garden or Farm by Annie Nova

Rooftop Veggie Garden Construction

Municipal Regulations

Before you set up a container vegetable garden on your roof, find out from your municipal council about the local zoning requirements and building codes.

If you’re not sure, ask the architects or building designers.

They can advise you on the building-code requirements for green roofs.

If you’re renting the property, check with your landlord, management, or building superintendent for permission to roof access.

For an apartment, sometimes some landlords and homeowners associations forbid growing plants on the rooftop.

Do not skip this step.

Otherwise, they will hold you accountable for damage or injury.

After you have gained access to the roof,

  • check for the upcoming maintenance to avoid clearing of your fixed structures and heavy containers by the contractors.
  • your planting space should not exceed 60 percent of the rooftop so, you can nurture your vegetables comfortably.

Green roofs not only retain rainwater, decreasing sewer discharge, but they also cool down the house’s temperature while also helping reduce air pollution.

T Magazine Singapore

Accessibility

Set up a green roof so you can access and work without much hassle.

Imagine carrying gardening tools, containers, bags of potting mix, and seedlings up and down.

Load on the Roof And Water Proofing

Understanding weight loads and structural integrity of the building is essential when creating a rooftop garden.

Can the rooftop sustain the weight of people and a mini vegetable farm?

Here is something to think about the roof load.

A 4×8 foot raised bed would weigh about 1,600lbs when it is wet!

Always consult a structural engineer or licensed contractor to determine how much load your roof can take.

You can grow anything in a container as long as it can thrive in a conventional garden. Expand your edible planting to fruits and berries, salad greens, and root vegetables – even asparagus, pumpkins, corn, and apples, apricots, peaches, pears, figs, and bananas.
Movable Harvests — The Simplicity & Bounty of Container Gardens by Chuck Crandall & Barbara Crandall

Plan ahead on the number of plants to grow and the type of containers to use.

Plants also become heavier as they grow.

Keep that in mind, when estimating the overall weight of your garden.

If weight is a concern, consider shallow beds for your rooftop garden.

Usually, the load-bearing areas focus on the perimeter of a roof, walls, or beams.

They are the best spots to place vegetable containers.

To grow vegetables that require more soil depth without committing to larger roof loads, use deeper containers in strategic spots (over your roof beam or posts).

Garden Therapy

Also, make sure your roof garden is waterproof when you have plants on top.

Otherwise, the water will seep into your home.

You should comply with the regulations to avoid paying for any damage if you flood your home or the roof collapses under the weight of your mini-farm.

Watch This Video

Water

No matter what type of rooftop garden you have, you need to figure out the kind of watering system to use.

Having a source of water nearby, such as a hose bib or faucet comes in handy.

I don’t think you want to carry watering cans all the way up.

If you don’t want to get it from your household, set up a few barrels to collect rainwater.

But check with your structural engineer if it can support the extra weight.

Usually, the rooftops tilt slightly to allow the rainwater to drain.

Check the gradient of the roof surface before placing the containers.

The water should seep from the pots and containers and flow to a drain.

Rooftop container gardens are oases that provide habitats for the city wildlife and safeguard endangered species.

Sun and Wind Exposure

Veggies on the rooftop are more exposed to sun and wind than a traditional garden.

Your container planting vegetables need a minimum of six hours of sunlight while sun-loving (heliophilous) edibles require at least ten.

So, take note of hours of sunlight.

Also, pay attention to nearby buildings that may create additional shades.

Usually, the wind blows stronger at rooftop than on the ground.

It can damage your crops.

To reduce the wind speed, build structural windbreakers along with the building frame.

Get rid of dead leaves and debris before your drain on the rooftop gets clogged.

TIP
Sketch a garden map to identify potential spots to put your containers. Prioritize lightweight and deep pots for your vegetables.

Safety

Make sure your green roof is safe.

Remember that roofs are windy places.

  • Install fences to prevent any gardening items from falling off the roof.
  • For passerby protection, secure pots, trellises, awnings, or windbreakers to railings.
  • Set up a barrier or guardrails around the perimeter of the roof to keep visitors safe.
  • Do not place the planters too close to the railings that kids can climb on or over them.

Next, we’ll look into containers, soil, drainage, watering, fertilizing, and vegetable plants for rooftop gardening.

How To Make A Rooftop Vegetable Garden

Choose The Right Container To Sustain A Roof-Load

Consider the size, weight, and material for rooftop containers.

Size

Different veggies need specific sizes to grow well.

Half-gallon to five-gallon planter is the best size for rooftop container gardens.

Make sure the pots are large enough for the roots of whatever plants you grow.

As a general rule, select as large a container as possible. Small containers dry out more quickly and may need daily watering.

Gardeners

Also, consider the depth of the pot for your vegetables.

TIP
If you’re using shallow containers, avoid large vines with a large leaf area. They can quickly deplete the water reserves of a shallow bed.

Plants with deep root systems need ample space, or else their growth will stunt.

The deeper the pot, the larger the storage of moist soil. You don’t have to water your vegetables so often.

Weight

If you feel uneasy about your roof load, the weight of the container can be a problem.

Containers become heavier after being saturated with water.

If you’re using clay, terra cotta, ceramic, and concrete ones, you’ll have a hard time trying to lift them.

Instead, opt for lighter options such as styrofoam boxes, fabric grow bags, plastic, lightweight wooden, or fiberglass planters.

You can move them around as seasons change.

But if you’re planting a tall or top-heavy vegetable, it will tip over the container.

Make sure the planters are wide and heavy enough to balance the weight of the top growth of your edible crops.

If your rooftop garden is windy, get large-sized pots such as half-barrel planters.

They are less likely to be blown away by the strong wind.

Material

Terra cotta, clay, and ceramic containers heat up more than synthetics.

It can cause the temperature in the soil to rise, resulting in more frequent watering.

TIP
Lift your veggie containers off the floor using wooden decks, pot feet, or concrete blocks so the air can circulate underneath. It will improve the drainage and keep the roof surface dry. The non-contact between the roots and the rooftop reduces the potential damage on the roofing materials.
Garden Tower Project

Self-Watering Containers For Rooftop Vegetable Gardens

Sub-irrigated planters (SIPS) contain reservoirs that increase the time between waterings.

They keep your plants on rooftops moist at all times.

You can also keep the depth of the pot to a minimum since the reservoir below the planting area provides the moisture.

Thus, your plants don’t need a lot of attention compared to traditional gardening.

Commercial sub-irrigated containers such as EarthBoxes are a useful option for growing vegetables on rooftops.

Raised Bed Gardening on Rooftop

Raised bed gardening means growing plants in soil that is higher than the ground.

It is suitable for any edible garden on the roofs.

The beds have to be at least 10-inches deep. It should hold enough soil for root growth.

If you want to avoid hurting your back, place the bed on stilts.

$83.29
in stock
1 new from $83.29
as of October 17, 2019 4:45 pm
Amazon.com
Free shipping
$98.79
$99.99
in stock
3 new from $98.79
as of October 17, 2019 4:45 pm
Amazon.com
Free shipping
$139.98
$146.76
in stock
8 new from $139.98
1 used from $128.72
as of October 17, 2019 4:45 pm
Amazon.com
Free shipping
$799.99
in stock
1 new from $799.99
as of October 17, 2019 4:45 pm
Amazon.com

Budget Rooftop Garden Planters

Don’t let cost keep you from gardening.

If you’re are a budget-conscious roof gardener, make your own planters from kiddy pools, unused wooden crates, barrels, old coffee cans, heavy-duty plastic shopping bags, tires, food buckets, and recycling bins.

As long as they can hold potting soil, you can use them.

You only need to drill holes in the bottom for drainage.

Watch this video about Rossana’s Rooftop Garden.

Lightweight Growing Medium For Green Roof

Are you choosing the right planting medium?

Avoid using gardening soil as it is heavy.

The fantastic thing about growing in containers and raised beds is that you have total control over the soil.

Having an excellent potting media, your plants can thrive, and you’ve less work.

TIP
If your rooftop garden receives a lot of rain, the growing media must dry out quickly.

For rooftop vegetable container gardening and raised beds, the soilless mix is your best friend.

  • It’s light, reducing the overall roof-load and allowing a higher soil depth for greater yields.
  • It holds water better than garden soil.
  • It aerates and drains well, providing breathing room for the roots and minimizing compaction.

You can find several good potting mixes on the market.

They contain sphagnum peat moss, pine bark, perlite, and vermiculite that are lighter than garden soil.

Peat moss is a fundamental component of rooftop gardening. It can retain moisture in the soil when it is dry and prevent excess water from killing roots when it is wet. When mixed with sand, it makes good soil for potted plants and vegetables, although it cannot replace the quality, efficiency, or sustainability of homemade compost.

Egypt Independent

For some gardeners, it can be time-consuming to make your compost when you can buy a potting mix. But it’s worth it. Because compost is both quality soil and natural fertilizer.

You can try Bokashi composting as it doesn’t release nasty smells.

It is a Japanese technique that breaks down your kitchen organic waste scraps such as meat, fish, and vegetable scraps using friendly bacteria, fungi, and yeast.

Besides compost, you can grow edibles in organic matters such as coir, wood chips, and rice hulls.

You can mix your own by combining 3 parts compost or composted manure with 1/4 part peat, for lightness. Add a handful of perlite per pot, for improved drainage.

The Spruce

How much soil you need depends on the type of veggie you want to plant.

If weight is not an issue for your green roof, fill up your container up to 12 inches deep.

It can support tall-growing vegetables such as tomatoes.

It offers enough root growth for even the most demanding of plants.

Remember to change the soil in the containers at least once a year.

You can grow vegetables in anything that can hold soil and has drainage holes in the bottom.

Drainage For Rooftop Gardens

Most gardeners use rocks or pottery shards for drainage.

For rooftop pots, you can try styrofoam peanuts as they are lightweight.

Raised planter beds with open bottoms lined with filter fabric allow for drainage.

Garden Therapy

Watering Your Rooftop Vegetable Growing Containers

Do you know that plants on rooftop beds will dry out quickly during dog days of summer?

You may even need to increase the watering frequency in a day.

The rooftop greens in containers also need a higher volume of water every day because

  • they are exposed to wind and sun
  • they need to thrive during the growing season

Drip Irrigation

If you don’t like the idea of spending most of your time watering your edible garden, or may lead a busy life, install an automatic irrigation system fed from roof-level spigots.

Once the system is in place, you can go away for several days at a time without worrying about your plants dying.

It’s the best way for your plants to get water consistently.

It comes with an auto controlling system and timer for water conservation.

You need to fill the reservoir with water every couple of days.

Your veggies absorb moisture as they need it.

But, the drip irrigation system needs regular maintenance.

Collect Rain Water

If your rooftop does not have a spigot, set up a rain barrel on your roof.

But make sure the roof can support the weight of a full water tank.

And you must have a perfect spot to position it.

If you don’t own the property or live in a condo, you need permission from your landlord or the building management before doing so.

For a house with a rooftop, you can always run a garden hose up the side of your building.

Watering Cans

Your last option is to haul watering cans up from your apartment.

I hope it doesn’t come to that stage.

It’s not worth the effort and time if you only have a few edible plants.

TIP
Instead of uprooting infected plants, use lightweight pots for quick isolation. It eliminates the risk of plant death.

Well, all hope is not lost.

You can use a plastic bottle drip irrigation system.

It is the cheapest drip watering system.

But it doesn’t have a timer.

The next important thing for rooftop container gardening is the timing.

You must maintain a schedule for watering your garden.

Water your vegetables the first three hours after sunrise and at night as the pots can retain the moisture longer.

If you want to reduce moisture loss, add some shades, and spread an even layer of mulch over the surface of the soil.

TIP
Mulching helps container vegetable gardening, especially in the warm weather. It provides a barrier against evaporation and enriches the soil after decomposition. So, start adding organic materials on the top of your potted vegetables.

Fertilize Your Vegetables On Rooftop

Even a great potting mix will become depleted over time, as plants take up the nutrients and the water leaches them out. The larger a plant grows, and the more water it takes, the faster the soil is depleted.

The Spruce

You need to fertilize rooftop container plants regularly at least every 2 weeks.

You can get quality organic fertilizers on the market.

If you want the quickest way for your veggies to get the nutrients, use a water-soluble fertilizer.

Either water the soil to allow the nutrients to go straight to the roots or spray the foliage.

TIP
You can make your own fish emulsion for feeding your vegetables. This DIY fertilizer combines dead fishes, molasses, and water. Pump in some oxygen to speed up fermentation. Soon, the good bacteria will multiply.

Take Advantage Of The Rooftop Sun Exposure

When you have a green roof, always tailor your container gardening to the available sunlight.

Fortunately, most roofs get full sun.

But too much of sun exposure can burn your edibles and increase watering frequency.

So how do you protect them?

Shade cloth and shade screens may be needed to protect crops. Retractable fabric awnings can be used or containers that can be easily moved to shaded areas on hot or windy days. Survey your rooftop in the morning, midday, and afternoon before deciding where to locate your containers.

HarvestToTable

If a neighboring building overshadows your rooftop vegetable garden most of the day, it is better to plant shade-loving greens.

Having a black painted roof during dog days can be tough on your edibles.

Make sure you plant veggies that can tolerate scorching temperatures.

TIP
Transplant starts to large containers on cloudy days to prevent sun and heat shock.

Reduce Wind Effects On Rooftop Crops

It can be turbulent on a roof if no nearby building offers any cover.

Wind exposure depends on the height of your rooftop garden.

The higher it is, the more exposed your garden.

Wind can absorb moisture from both plants and containers.

Here are a few measures you can adopt to dampen wind speed.

  • Plant wind-tolerant vegetables such as dwarf varieties, herbs, and leafy greens.
  • Grow some barrier shrubs.
  • Erect screens of woven reed or bamboo, latticed windbreakers, and trellising.
  • Choose low containers that hug the perimeter walls.
  • Leave a gap of a few inches from the edge of your container.
  • Secure any lightweight pots to railings.
  • Tie down all your rooftop furnishings, gardening equipment, and supplies.
  • Place bricks in containers, under the soil.

Dealing With Weeds and Pests On Green Roof

Devote some time during summer to remove the weeds.

With rooftop gardening, you’ve less worry about deer or rabbits nibbling your plants.

But, you need to check for insects on your container planting vegetables.

Monitor your plants and try to catch problems while they’re small.

This way, you don’t have to resort to chemical intervention.

Rooftops can be gusty. They can invite mugwort, clover, or a feral maple in your container garden.

TIP
Planting vegetables in containers on rooftops is a form of urban gardening. It’s also an effective way to avoid sharing their harvest with deer, rabbits, and woodchucks. It’s ideal for gardeners who have limited space, physical disabilities, and poor soil conditions such as clay, stone, and sand.

Protect Rooftop Veggies From The Winter

Plants in container vegetable gardens have to deal with harsher climates than ground-level ones, especially during the winter.

  • Identify the types of crops that need winter protection.
  • You can bring smaller ones inside.
  • You winterize large perennial vegetables with extra mulch.

Tools For Rooftop Gardening

Unlike traditional gardening, you don’t need a lot of tools for a rooftop container garden.

You can begin with a trowel and a soil scoop since you spend most of the time scooping and filling.

You can get a small tarp to keep the soil in place when emptying the pot.

If some plants need pruning, a good pair of pruners can be handy.

For additional tools, it all depends on your vegetables and the amount of maintenance you want to do.

It’s no fun lugging tools, fertilizers, and soil up to the roof every time you want to garden. A small storage space—even if it’s just a simple wooden box—will keep supplies handy and prevent them from blowing around on a windy rooftop.

HGTV

What Type Of Vegetable Plants Are Good For Rooftop Container Gardening

Most rooftop gardens are hotter during the day and gustier than the ground-level ones.

So, the veggies for rooftop growing must withstand brutal conditions.

  • Drought-and-heat-tolerant plants.
  • Vegetables with limited root systems since they don’t need a lot of soil.
  • Some varieties of climbing beans as they can endure consistent exposure to the wind.
  • Root vegetables because they don’t have thin central stems. Their thick roots also make a strong foothold in the ground, protecting them against the wind.
  • Shallow-rooted edibles.
TIP
A native edible plant is perfect for green roofs. It has survived in a specific place for a long time. Thus, it can tolerate a harsh environment, soil, temperature, or even pests.

The bad news is that just like the ground-planted edibles, the rooftop container-grown vegetables may not escape the winter chill.

Easiest Vegetables To Grow In Containers On Your Rooftop Garden

Growing vegetables on green roofs make the most of your urban garden space.

Leafy greens like lettuce, arugula, and spinach are the easiest crops for beginners.

And you don’t have to grow a lot of them for the maximum yield.

TIP
Vegetable containers should sit flat against the roof, so they don’t topple over.

Imagine with a single square meter of lettuce, you can harvest up to a hundred bunches in three weeks.

Try out some easy-to-grow edible plants below.

Tomatoes

  • Grow well in sweltering conditions when you use large containers.
  • Need at least 5-6 hours of sunlight.

Peppers and Chilies

  • High yields.
  • Vulnerable to aphids.

Eggplants

  • 6-8 hours of sun exposure for heavy fruiting.
  • A heavy feeder.
  • Staking or caging for support.

Lettuce

  • Loves cool weather.
  • Continuous harvest.
  • Light, frequent, and consistent watering to keep the soil slightly moist.
TIP
Start growing vegetables in containers under the screens or netting. It’ll prevent the soil from drying out.

Spinach

Dwarf Squash

$4.95
$5.95
in stock
1 new from $4.95
as of October 17, 2019 4:45 pm
Amazon.com
$5.93
$6.93
in stock
1 new from $5.93
as of October 17, 2019 4:45 pm
Amazon.com
$16.00
out of stock
1 new from $16.00
as of October 17, 2019 4:45 pm
Amazon.com

Beans

  • Sun lover.
  • Need a trellis for support.
  • Nitrogen fixer.
  • Savory, kale, spinach, and celery as companion plants.

Cucumber

  • Keep the soil slightly moist.
  • Reduce water stress by mulching to overcome bitterness.
  • Prone to mildew, so don’t wet the foliage.

Carrots

  • 1-2 sq ft. of growing space with a trellis.
  • Need full sun.

Also Read: 5 Gallon Container Vegetable Gardening

Radishes

  • Fast growing.
  • Allow 2 inches of space between each plant.
TIP
If you plan to move the vegetable containers around, place them and leave them on locking dollies.

Peas

  • Limited growing season.
  • Need partial sun.
  • Fix nitrogen in the soil, making them an ideal companion plant.

Beets

  • Fast-growing edibles.
  • Don’t plant if the pH of the soil less than 6.0.
  • For well-developed beets, thin the seedlings down to one seedling after they appear.
$9.40
$14.95
in stock
1 new from $9.40
as of October 18, 2019 1:48 am
Amazon.com
Free shipping
$9.50
in stock
1 new from $9.50
as of October 18, 2019 1:48 am
Amazon.com

Cabbage

  • Prefer sandy to clay type loamy soil with good drainage.
  • Its roots grow at a shallow level.
  • For sweetness, let it matures in cool weather.

Chard

  • Vigorous root growth.
  • Requires thinning.

Planting in pots as opposed to the ground’s soil limits the nutrient diversity a plant derives — hence, companion planting is necessary.

T Magazine Singapore

Rooftop Garden Ideas

Make your rooftop garden a place to relax with a comfortable chaise longue to bask amid jasmines, frangipani, Cestrum nocturnum (night-blooming jessamine with a high-pitch, sweet scent after dark), anise hyssop, and passionflowers.

BHG

Start with evergreen plants such as box and sweet bay. Lavender also provides a year-round green base, but it won’t flower all the time. Then add your favourite colours with flowering perennials. For example, agapanthus, bleeding heart, campanula, and clematis. They have a long blooming period and will come back next year.

The Guardian

When laying out the beds and containers, leave space for a small table and chairs. Large pots of dwarf fruit trees or trellised crops can be arranged around the nook to offer privacy from nearby buildings and for creating an oasis in the middle of the city.

HGTV

Choose containers that create focal points. Spend money on a couple of larger containers rather than on lots of smaller ones. Too many plants or ornaments make a small space look overcrowded.

The Guardian

Takeaway

If you’re living in an apartment, you can still have an edible garden.

You can grow a surprising amount of food on your roof, even if it is a small space.

The only exception is that you need to water and feed your vegetable plants more frequently.

Start small and gradually increase your urban garden as you gain more experience.

Share This
Rooftop Container Vegetable Gardening Post Graphic
Like this post on rooftop container vegetable gardening? Remember to Save it on Pinterest!

Do NOT follow this link or you will be banned from the site!
%d bloggers like this: