Gardening

How to Make a Rooftop Garden : 101

Last updated: October 14, 2022

Are you live in an urban area?

Love gardening or wish to start one?

Have a box of questions or confusion about starting a rooftop garden?

Be cool.

Here I will explain everything to wash out your confusion about a rooftop garden. Moreover, I will show you some solutions to start a rooftop terrace.

In urban areas, there is limited space for living, so managing a place for your garden is hard sometimes.

But if you think vertically, it is still possible to transform your apartment building roof into a charming outdoor garden and enjoy Mother Nature’s flavor.

How To Make A Rooftop Garden

Benefits of Roof Gardening

  • Best uses of available places on the roof.
  • Roof gardening can improve air quality and protect your building from overheating.
  • Attracts wildlife like bees, birds, butterflies, and other species.
  • No wild animal hazards like deer.
  • Create a private place for passing your leisure.
  • A roof garden is the symbol of urban agriculture.
  • It can balance the summer and winter temperatures.
  • Reduce the demand for extra energy.

Difference between Green Roof and Roof Garden

First, you must be clear that I am talking about roof gardening, not green roofing.

Roof gardening can be different based on your design and demand. Sometimes it covers the whole roof as a regular garden. And sometimes partially uses pots or raised beds.

Roof gardening mainly focuses on recreational activities, growing plants, creating an outdoor place for entertaining people, and spending quality time.

On the other hand, the green roof mainly covers the whole top to strengthen building structures.

It also saves energy by controlling the building temperature in the summer and winter seasons. Moreover, it keeps your money and the environment.

So, continue reading if you want the answer to making a roof garden.

Tips for Making a Rooftop Garden as a Beginner:

First, you must have an open roof to rent or own an apartment in a shared building.

Don’t waste your time and money moving further if you haven’t. You better start indoor gardening or balcony gardening.

If you have a roof, the following steps to consider building a roof garden.

1- Getting Permission

Check with your local planning office for the ordinances or city’s building codes to ensure that you are allowed to start a roof garden in your area.

Live in a rented house or an apartment in a shared building. You must get permission from the landlord, condo organizations, or homeowners association to begin a rooftop garden.

If the laws allow you to do so, you can go for it.

2- Contact an Engineer

Consult with a licensed building expert or architect about the possibilities and challenges of starting a roof garden in the building where you are living.

For example, some buildings cannot hold the extra load. But, on the other hand, some buildings can take a limited amount of weight.

You don’t need an architect to complete the whole roof garden design. But an architect, building expert, or contractor can explain to you the loading capacity of your building, which includes:

  • Your plants
  • Garden containers
  • Other required equipment
  • Furniture
  • People and
  • Weather loads like snow

Even if your building can handle the extra weight, use lightweight materials like plastic, fiberglass, or foam planting containers.

In addition, use coco peat or light potting soil to set up your garden.

Remember, your garden design mostly depends on the roof’s weight capacity. Besides, consult an engineer about the materials best for your roof drainage system.

3- Safety Comes First

Protecting the roof from falling off or weight capacity doesn’t cover everything.

You have to ensure the safety of the passerby from falling tools because roofs are commonly windy places.

So round your roof with fencing. You must follow the guidelines of fence height according to the local garden law.

Don’t try to skip these steps, and try secretly continuing gardening on your roof. It will cost you, and you will find yourself liable for damage and injury.

At the same time, observe the roof’s general condition; if any upcoming maintenance is required, you may have to move your planters and other structures, which would be expensive.

4- Approximate Cost for Roof Garden Construction

It is hard to determine how much it costs to build a roof garden. There have many factors that may vary the cost of making your roof garden, such as:

4.1- Method:

Which method do you choose for your roof?

Container on the terrace, raised bed on the top, or a permanent one like ground-level gardening.

4.2- Weight Capacity:

Weight capacity and the present condition of your building influence the gardening budget.

Suppose the building roof needs routine repair or maintenance before starting a garden.

In that case, it can merge with the garden construction cost.

4.3- Garden Design:

Your garden design mostly depends on the load capacity of your building roof.

If the load capacity of your building is not enough, you must have to apply a simple design that can reduce your cost.

4.4- Consult with an Expert:

You need a building consultant to know the exact condition and procedures to build a roof garden, but a landscaping designer is not essential.

So, if you design your garden, you can reduce your cost.

4.5- Budget:

Choosing costly plants unavailable in your area will raise your gardening cost.

4.6- Water Supply System:

If your roof has no water supply system, you have to create one, and it will increase your cost.

4.7- Drainage and Irrigation System:

Besides, creating a drainage system and installing an auto irrigation system can raise your garden budget.

Typically, roof gardening construction costs are a bit higher than conventional. It starts from $20 to $200 per square foot based on the above factors and other hidden or situational factors. Consult with a building expert or landscaper to get a more specific idea about the cost.

5- Sunlight Exposure

Sunlight plays a vital role in growing plants. So, observe your roof to know how much daylight it receives daily. Besides, check the year-round to understand the sunlight and shade time frame.

Moreover, sunlight determines which plants grow well in your garden.

Therefore, if your garden receives enough daylight without any obstacles for 6 to 8 hours, choose the plant varieties to increase well in sunlight.

On the other hand, if the garden receives limited sunlight because of neighboring buildings most of the day, choose shade-loving plants.

 6- Water Supply and Drainage

There are multiple ways to start gardening on the roof, such as:

  • Container gardening
  • Raising several beds
  • Planting or preparing your whole roof as a garden

So, before starting a garden, you must properly plan your rooftop garden irrigation system based on which gardening method you follow.

There are several methods of irrigation systems, and they depend on the design of your garden.

Arrange a water storage system based on the demand of your garden size. Your garden needs daily watering because of the wind and sun exposure.

So, providing the necessary water supply can make the best of it.

You can use automatic drip irrigation or a plastic bottle watering system or manually water your plants if your garden is too small.

Besides, the proper drainage system is essential when planning for your roof garden construction. It also depends on the garden design you choose.

To protect your roof from damage, put plastic trays or rubber layers beneath your containers or beds to help them drain quickly.

7- Wind Exposure

A rooftop garden is windier than a backyard garden.

Besides, if your building is higher than the adjacent buildings or not surrounded by high-rise buildings, the wind will be extreme.

A strong wind can harm your plants, damage your garden structures and occur an accident.

Don’t try to put a plain block shield to prevent such a strong wind because it can happen more damage.

Instead, you better control the wind by reducing its force using trellises or some wide structural frame.

Always avoid lightweight equipment when selecting furniture or other essential materials for your roof garden.

8- Soil and Container

When starting a garden on the roof, you must consider the soil mix, which must be lightweight.

It would help if you did not use the same soil mix used for a ground-level garden because a typical soil mix is heavier than the unique light potting soil mix.

To make a lightweight potting soil mix, you must collect vermiculite, topsoil, coir fiber or coco peat, limestone, compost, coarse perlite, and sand.

Then, moisten those ingredients and combine them perfectly.

This potting soil mix will be lighter than other garden soil mixes and improve your drainage system.

Pick up a suitable container for your garden is also essential.

You must choose plastic or wooden planters for your roof garden and try to avoid terra-cotta or concrete planters to reduce the extra weight.

Suppose you want to cut off your expenditure. In that case, you can arrange some-

  • Old plastic buckets
  • Kids’ bathtubs
  • Small-size plastic drums
  • Coffee cans, and
  • Other unused waste materials

Which can hold enough potting soil for garden plants. Make holes at the bottom of the collected planters to release extra water.

9- Plant Selection for a Roof Garden

Selecting plants is a vital part of your garden. It depends on the –

  • Purpose of use
  • Weight load
  • Garden design
  • Space
  • Structure
  • Sunlight
  • Wind exposure

So, you must choose carefully the plants you are going to grow as follows-

9.1- Vegetable Garden:

If you want to create a vegetable garden, ensure your existing garden decoration, load capacity, space, and other factors allow the varieties you choose.

9.2- Sunlight Exposure:

If high-rise buildings surround your roof, never choose the varieties to need full-day sunlight. Instead, pick some shade-loving plants.

Besides, avoid those plants that can’t survive in a strong wind.

You can grow some edible plants if your roof garden receives enough sunlight.

There has plenty of varieties, and you can try different types each year.

9.3- Flower Garden:

On the other hand, when you start a flower garden, you can pick any flower.

But, remember the sunlight and wind exposure and avoid those plants that grow taller and spread branches.

9.4- Pick Native and Drought-Tolerant Plant Varieties:

Selecting native and drought-tolerant plant varieties is the most crucial part of plant selection.

In addition, the native plants attract the bees, birds, and other pollinators in the garden. So, always pick up the local plant varieties for the betterment of nature.

10- Electrical Wiring

If you want to arrange a party in your roof garden at night, you need a provision for lighting. Besides, it is also essential when you need to work at night in your garden.

11- Storage Box

Installing a storage box on your rooftop can save you time and labor and make your work easier.

For example, you can keep garden tools and other necessary things in the storage box to find them easily.

In addition, you can turn your system box into a table or seating bench in a decorative way.

12- Roof Maintenance

A routine checkup of your roof is essential when starting gardening. Regular inspection helps you to avoid unexpected damages and saves you money.

Make your checklist and timetable for the routine checkup of your building roof.

Check the interior of your building, too.

Suppose there is any sign of water damage-repair, immediately. It may happen for high snow falling or leakage of water supply, or your building roof takes an extra load for your garden.

Waterproofing your roof membrane is essential to protect it from water damage.

Besides, plant roots can harm your roof, so use root repellant if required.

Ensure your roof is free from fallen leaves, tree limbs, dirt, and debris, which can clog your drainage system.

Pipes and other equipment fittings are one of the main parts of roof maintenance. First, check the fittings and ensure no leakage or dripping water. If so, repair it immediately.

Recheck your old repairs and drainage system, and always keep your roof dry and clean.

13- Weeds and Pests

Spend some time weeding and filtering dead leaves in your garden.

Check regularly if bugs and diseases attack your plants.

Remove the detected leaves and plants as soon as possible and use organic pesticides if required.

14- Winter Care of Your Garden

You must determine the following type of protection during winter for your roof garden-

14.1- Study USDA Plant Hardiness Zone

You can study the USDA plant hardiness zone to understand the average minimum temperature of your garden location.

Most importantly, it may depend on the micro-climate of your garden location-like, sunlight and wind exposure, and the surroundings.

14.2- Pick Hardy Plants:

After acquiring knowledge and observing your garden location and environment, you can take some need-based actions to protect your garden from winter.

The rooftop atmosphere is more challenging than the ground-level garden location, and it becomes harsher in winter.

Therefore, try to select those plants which need less protection and are hardy enough to survive during the winter season, and avoid picking the tender plants.

14.3- Use Slow-Released Fertilizer:

You better choose slow-release fertilizers rather than high-nitrogen fertilizers at the beginning and late in the year for more precaution.

In addition, it will help you to minimize the risk of damaging the effects of your garden plants.

14.4- Cover Garden Plants:

In addition, cover your garden plants with a black plastic layer to protect them from the morning sun and heavy snow falling. The morning sun can harm the growth of plants during winter.

14.5- Use Special Containers:

Some low-growing container plants can be moved inside your house for protection from cold.

Use a frost-proofing garden container to protect them from cracking.

As well as apply compost soil with a mixture of straw and old leaves, which will make more accessible the drainage system more and keep the soil moistened.

14.6- Mulching:

Mulch your soil to keep them from freezing, which will help moisturize the ground during winter.

A light layer of snow is an insulator and protects plants from cold and frost. But, when you face heavy snow in your garden, shake the trees and shrubs to remove snow before breaking them.

14.7- Greenhouse:

If you create a greenhouse to protect your garden from winter, don’t let the snow stay on your greenhouse roof for a long time.

Instead, remove the snow immediately before it damages your roof and frame.

You can check out here for details about winter protection of your garden.

15- Beautify Your Garden

Whether your garden is big or small, the proper decoration will give it a beautiful look.

Make a sitting arrangement for guests in your roof garden. If you haven’t enough space, at least keep a deck chair for you personally or some folding chairs for limited guests.

This little sitting arrangement will give you the pleasure and inspiration to go the extra mile.

Because only work without entertainment can make you feel bored after someday and you may give up. Make your garden a place of fun and work.

You can also put some garden light in your garden to make it more gorgeous.

In addition, you can set up a water fountain in a suitable place on your rooftop garden.

Disadvantages of a Roof Garden

It goes without saying; roof gardening can benefit you in many ways. But it also brings you some problems.

Don’t be scared.

They are not unsolvable. But regarding the issues before starting a garden can help you to make a proper plan and reduce the risk of failing.

You need to know that garden container and raised beds can damage your roof for holding extra weight, and strong wind can harm your plants and seedlings.

It will be challenging if your roof has no options to get a connection to the water supply. Besides, any water leakage can damage your roof.

Moreover, water can soak down from your top to the outside without a proper drainage system.

The initial investment for a roof garden is costly, comparing a ground-level garden.

Regarding the safety issue of the building and the surrounding people, the insurance company significantly charges a higher rate for the roof garden.

When you start a park on the roof, regular maintenance is essential, and sometimes you cannot handle it without the help of an expert hand, which is expensive too.

Conclusion

Just keep the above tips in your mind when you plan for a roof garden. Every action in our life has good and bad effects, and every problem must have a solution.

Proper planning, patience, and passion, investing time and money in the right way for your garden can make the best of it.

No matter how big or small your garden is! It will bring you peace and allow you to spend quality time with Mother Nature.

John Michael
John Michael is a self-help writer and a hobby gardener. Michael’s passion in writing is to inspire the beginner gardeners to not just “hang in there” or “make it through” but to thrive. He does this through blogging.

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