Updated: October 18, 2022
Typically, around a 700 sq. ft. vegetable garden can supply the demand of a family of six members all year round.
So as an urban resident, vegetable gardening on the roof is a smart choice for you. It brings you an opportunity to get fresh food, exercise, and fulfill your hobby.
Proper planning before you start will make the job easier for you. In addition, you also have some hidden benefits you couldn’t feel before you start.
This article gives you step-by-step instructions to complete your rooftop vegetable garden.
Step-1: Things to Be Considered Before Starting a Rooftop Garden
Creating a roof garden depends on issues like –
- Unused space on your roof,
- Permission to use the roof as a garden,
- Following local municipality, garden, or homeowners’ association laws.
Load Capacity: You need to consult with an engineer to check the load capacity of your building roof.
Surroundings: Observing the surrounding environment (high-rise building) of your building is essential.
Sunlight: It would help if you had a little research about sunlight exposure on your top.
Wind Exposure: Consider the wind flow over the roof to take the necessary steps to prepare the garden design.
Watering and Drainage System: You must consider the water supply sources and drainage system for the garden on the roof.
After considering the above issues, you can go to your next step.
Step 2: Methods of Building a Rooftop Vegetable Garden
After considering the preliminary issues for setting up a roof garden, you must concentrate on the construction methods.
You can build a roof garden in three different ways:
- Container gardening
- Raised bed gardening
- Regular landscaping (covering all over the roof or selecting part of a roof as a ground-level garden).
Container gardening is the best choice if you have limited or small space.
You can vertically design your vegetable garden using plastic bottles on the wall.
Besides, you can also arrange broad PVC pipe, creating holes, filling them with potting soil, and placing them in a multi-story frame structure.
Also, you can use a reasonable height shelf, placing multiple containers on it.
But always keep in mind the load capacity of your building roof, available water supply, and proper drainage system.
If you have a limited budget use the followings-
- Unused plastic containers
- Wooden boxes
- Heavy-duty black poly bags
- Waste bins,
- New kids’ bathtubs,
- Old kitchen kits
- Things that can contain soil for plants as a planter.
Make the necessary holes at the bottom of each container according to the container size for the drainage system.
Always keep a tray at the bottom of each container or structure to hold water used for irrigation of the garden plants. It will protect your building roof from damage and keep it dry.
Usually, you can cultivate all types of vegetables in a container, but choose the varieties better grown in containers.
Finally, when you buy seed from the seed market, check out the seed packet to confirm whether the types are applicable for containers or not.
Raised Bed Method
Making a raised bed vegetable garden on the roof is more flexible than a container-based garden.
Here you get enough room to decorate your garden the way you want.
But the making process of a raised bed garden on the roof differs slightly from a conventionally grown bed.
For a conventional raised bed garden, you don’t need to consider load capacity and water leakage issues.
So, it would be best to take extra protection when creating a raised bed on the roof.
- Measure the length and width of the overall garden area.
- Determine the size and shape of the raised bed.
- Choose suitable materials and make a decent layout design with the specification of your raised bed vegetable garden.
- The wooden structure is the most commonly used material for the raised bed garden.
- And, of course, you must avoid heavy materials when designing a rooftop garden.
- Follow the layout design and the specifications you choose to apply for your raised bed garden.
- Determine the Height-Length-Width-Depth of the frame of your raised bed according to the minimum space and depth required for the plants you want to grow in the bed.
- Usually, the average minimum height of a raised bed shouldn’t be lower than 6 inches, but 12 inches is standard, and higher is better.
- Your raised bed length and width should be flexible-sized if you want to change the design in the future.
- This simple trick can help you to change the design easily without changing the frame structure of the beds.
- For example, if you make a bed that is 12 feet long and 6 feet wide, don’t make a full-length single frame as the requirement.
- You better divide it into 3’/6′ or 3’/3′ or 3’/4′ feet.
- This simple trick will ultimately give you the exact size when you put them together.
- Besides, keep a particular space for the walkway between two beds in your layout design.
- This trick will help you move from one bed to another to nurture the plant’s irrigation and other purposes.
- Setting up the plastic tray on your roof to confirm that water doesn’t seep into your roof, then place the raised bed frame on it.
- You can install the planter’s frame on a low-height flat stand or a deck to protect your roof from seeping water.
- After placing the raised bed frame on a tray or deck, staple up a chicken wire at the bottom of the frame.
- Then, put a weed cloth or landscaping fabric on top of the chicken wire and fill up the bed with potting soil, compost mix, and other necessary components.
- For more flexibility, you can place your whole raised bed on a rolling frame for easy moving.
Method for Constructing a Regular Landscaping Garden on the Roof:
Landscaping a garden on the top is more challenging and expensive than the previous two methods. It covers the roof as a ground-level garden.
You can easily start a container or raised bed gardening by consulting an engineer, but the expert hand is not always essential.
But, it would help if you needed experts support to construct a landscaping garden on the roof.
To create a landscaping garden, you must ensure the following technical steps, which you can’t do alone.
Step 1- Waterproofing:
This is essential in roof gardening construction, whether you grow plants on a container or raised bed. But, landscaping waterproofing is more expensive than others.
The waterproofing layer protects the roof from seeping water and resists unwanted damage.
Step 2- Insulation:
This layer controls temperature fluctuation and resists moisture leaks. It makes more robust the overall structure more.
Fiberglass, mineral wool, polyurethane foam, and polystyrene are most commonly used for insulation.
Step 3- Drainage System:
The drainage layer helps to release the rainwater quickly from the soil bed.
Step 4-Landscaping Fabric:
This layer filters the water from the soil layer through the drainage layer. It also protects the drainage layer from clogging soil and other particles from the upper layer.
Step 5- Soil layer:
This is the layer where you’ll grow plants. Please fill your garden area with potting soil, compost, and other essential particles, making it water-permeable.
The depth of the soil layer depends on the plants you want to grow on it.
Step 3: How to Choose the Suitable Container for Your Rooftop Garden
Selecting a suitable planter for your vegetable garden depends on your situation, demand, and other factors. Here I explain the major factors influencing the selection of suitable planters.
This is the most critical factor that helps to choose the suitable planter.
Different plants have different shapes and sizes and need separate spaces to grow. And so, selecting the suitable planter mainly depends on the plants you want to grow in your garden.
It’s also very accurate that you will never grow the same plant all the time.
In that case, you better choose a standard-size planter capable of supporting the vegetables and herbs you want to grow.
Typically, a half-gallon container to a five-gallon container is a standard size for most plants.
Plastic containers are lighter than other containers. Therefore, they are suitable for roof gardens or wall decorations, or hanging on your balcony.
They look pretty simple and moisten the potting soil for a long time. Moreover, they are cheaper than terra-cotta or ceramics containers.
On the other hand, terra-cotta, ceramics, or clay containers are expensive. They are very lucrative but heavier than plastic containers.
Besides, the potting soil dries sooner in terra-cotta containers, so you need to water the plants regularly and take more care.
If you are budget conscious, pick plastic containers for your garden or unused household material containing potting soil for your plants.
On the other hand, if you mainly focus on the design of your garden, pick terra-cotta or ceramics containers or whatever you wish.
Load capacity is another variable influences deciding garden planters. Usually, lightweight planters are best for a rooftop garden, so avoid heavy-weight growers like terra-cotta or clay.
Suppose your rooftop has a shortage of space. In that case, it can also persuade of selecting planters to manage your limited spaces with good planter design.
Step- 4: Considering the Growing Medium
Preparing soil for your roof garden is different from the conventional garden.
Soil mix for your rooftop garden must be lighter than a regular soil mix, but only lightweight soil can’t solve all the issues. There have some other factors to be considered.
If your garden area receives enough rainwater during the growing season and the average rainfall ratio is higher, you would need a soil mix that dries out quickly.
But if you have an area that receives less rainwater and humidity, try to use a soil mix that holds water for a long time.
Besides, your plant selection also influences choosing the suitable growing medium. For example, some plants need less water, and others need more water than average.
So, when thinking of roof gardening, you must remember the weather condition in your garden area, the type of plants, and the lightweight potting soil.
Step- 5: Watering Your Plants
The irrigation system is one of the essential parts of gardening. Unfortunately, urban people lead a busy life, and sometimes it is hard to manage regular nurturing and watering the garden plants.
But you can’t skip out on this part anyway.
- The drip irrigation system is the most effective for watering your rooftop garden plants.
- This is an expensive system comparing other irrigation systems, which need regular maintenance.
- However, it has an auto-controlling system and timer, which can save water and protect your plants from damage.
- If you plan for a container garden, sprinkler irrigation systems are ineffective, particularly for roof gardening.
- Besides, this system wastes some water and evaporates quickly in the dry season. Best suited for lawn gardens and raised beds.
- The plastic bottle drip irrigation system is the most cost-effective and easy watering system than others.
- It provides similar support to the drip irrigation system. Still, you have to control it manually, and no option for setting a timer.
- Traditional irrigation system needs labor regularly. You can use watering cans with a small garden or a hose pipe to irrigate your roof garden.
Timing is another vital factor in watering your garden. You must have to maintain a schedule for watering your garden.
It is the perfect time for irrigation for the first three hours after sunrise and the last three hours before sunset.
Always remember never to water your garden plants in the middle of the day and after the evening.
Step- 6: Vegetable Plants Diseases and Pests Problems
Naturally, plants get infections. There are many ways your garden plants become infected or attacked by pests.
Pests can harm vegetable leaves, reduce production, and destroy whole crops. Your vegetable garden fruits can also be affected by problems and bugs.
When you notice any symptoms of diseases, immediately get rid of the infected leaves and fruits and apply organic pesticides if required.
Sometimes your garden plants become weaker and gray due to a lack of nutrients, soil condition, irrigation, and proper care.
Fungal diseases and viruses are other challenges for your vegetable plants that can destroy your yield.
Steps-7: How to Choose Vegetables and Herbs for Your Roof Garden
You can grow whatever you wish in your garden, but you must consider some significant factors before growing any plants in your garden to reduce the risk of failure.
You must be well concerned about the micro-climate in your garden area and the plants you choose to grow.
Do the selected plants have sun-lovers or shade-lovers? Do they grow well in cold weather or hot weather?
Most vegetables and herbs need ½ gallon container to a 5-gallon container to grow better. You need to know which container size best suits your growing plants.
Soil Depth Requirements:
Select your vegetable plants and herbs based on the depth of your garden container and raised bed. Or, collect some containers based on the plants you wish to grow.
Best time to grow:
Every plant has a growing season. When you choose the plants, keep in mind the increasing season of each plant. Perfect planting time will give you a better result.
Some plants need less care and maintenance. Proper fertilization and irrigation will give you the best result. Besides, arrange climbing aid when the plants demand them.
Some vegetables have particular varieties that grow well in a container or raised bed. Find those varieties in the seed market and follow the seed packet instructions for suitable types.
To best utilize your garden space, you can grow two or more friendly vegetables and herbs at once.
First, select the plants you want to grow in the garden, and then determine which vegetables grow well together with your chosen plants.
Some vegetables don’t grow together and hamper your main crops’ normal growth and harvest. So, you should carefully select the companion plants for your garden.
Does Roof Vegetable Gardening Save Money?
Starting a vegetable garden on the roof is very common. Still, when the question arises, “does it save Money?” there needs to be an explanation to answer the question.
Technically speaking, the answer is yes. But the following factors influence the calculation of your account accurately.
These factors help to calculate the return on investment in your garden and how much money you can save.
It would be best if you produced something you need for your family and they like to eat. Don’t invest your money in something which is not necessary.
Produce Something Expensive:
No matter what you produce, it would be best if you had time, labor, and money. So, make something expensive that can help you curtail your grocery budget.
Produce Something That Can Preserve:
You can’t consume all of your garden production at a time if you get a bulk display. So, produce something that can be canned, frozen, or preserving other ways.
The roof garden needs some extra cost for waterproofing and drainage system. So start on a small scale to realize the real scenario and hidden facts to avoid the risk of failure.
Minimize Your Cost:
Choose some unused lightweight household materials for your roof garden, growing from seeds instead of seedlings, and use homemade compost to minimize cost.
Calculate Time, Labor, And Investment:
Calculating your time, labor, and investment is essential to determine how much money you can save from your garden.
First, calculate how much time you spend over the year multiplied by the per-hour minimum value of your time.
Also include the cost of seeds, fertilizer, garden tools, and other costs to count the total investment.
Then, measure your season-end produce multiplied by the per pound value of your production to count the total output.
Finally, exclude the total investment value from the entire production value to get the return on your investment.
Gardening also has some hidden benefits which you cannot measure by money. You can only feel it to measure its value.
- Health Benefits: Gardening is an excellent natural exercise. Besides, it kills your loneliness and makes your mood better. Moreover, this is an excellent source of vitamin D.
- Fresh-Grown Food: Gardening creates an opportunity for chemical-free fresh food.
- Tasty Food: Homegrown vegetables and fruits are more delicious than the fruits of the grocery store.
- Create a Private Place: Gardening gives you a secret place to spend some time of your own.
- Create A Food Habit: Gardening attracts your kids to take homegrown fruits and vegetables and inspires them to do it.
Reading this conclusion proves that you are very serious about starting a garden. Make a simple plan, do some research and go for it.
Don’t overthink it.
As a beginner, gardening has no loss if you don’t start it commercially.
You will learn many things after staring at your garden, which I won’t mention here. The fact is nobody can tell you accurately.
It would help if you had to start to know the insights of gardening.
So, you better start today.
One thought on “Best beginners guide to grow vegetables on rooftop garden”
Hi John Michael
I am just about to start a roof-top vegetables garden and I happened to find your detailed write-up. It was a fantastic reading and will surely help me in finding way through my journey ahead. Please keep it up. Wish you best. Cheers