About Vermicasting


Vermicasting, done in a systematic way, transforms food waste into a rich, odorless fertilizer, and quite fast. Dr. Hala Chaoui from Urban Farms Organic, Inc. (UFO) explains how to use free tools developed by UFO to design your own effective vermicasting system.

Food scraps can be processed through earthworms into a rich fertilizer which is called vermicasting. Vermicasting is a wonderful source of fertilizer for balcony gardeners. Earthworm casts (vermicast) are a nutritious organic fertilizer for houseplants too. A vermicasting system can be sized to process the daily food scraps of small or large households and can be set up indoors or outdoors (on a balcony!). 

If designed around the earthworms’ feeding requirements, vermicasting does not produce odor or attract flies. Earthworms can survive at temperatures between 0 and 35 degrees Celsius, so insulation during winter and/or a reflective surface in summer might be needed. The worms perform best at room temperature (25 degrees Celsius).

Red Wigglers (or Eisenia foetida) are the earthworms of choice for processing waste. I summarized the biology of earthworms and their feeding requirements in a Vermicasting Factsheet written for OMAFRA (Ontario Ministry of Agriculture, Food and Rural Affairs). The ideal feed of Red Wigglers is a biodegradable waste mix with a carbon to nitrogen (C/N) ratio of 25, a bulk density of less than 640 grams/litre, and 75% moisture. Earthworms do not tolerate high salinity levels, which is why material like broilers’ waste needs to be pre-composted before use, and compost amended with NPK cannot be used in the mixture. Acidity should be kept low, so dairy, eggs, meat and fruits need to be limited to less than 20% of the mixture volume. Detergents and other toxins need to be avoided.

Earthworms need to absorb both oxygen and water through their skin to survive. This is achieved by placing them and their medium in a porous 5-sided container. A container made of 4 mm screen walls will allow air in and keep excess water out, to maintain earthworms’ optimal living conditions. Earthworms are sensitive to all light waves except the color blue. This is why the porous container needs to be encased in a light-tight outer container, to allow the earthworms to safely reach for the waste at the surface. They do not tolerate alcohol or heat, so to prevent waste from fermenting or heating up, the waste layer (and the container height) needs to be 30 cm or less. Earthworms can eat 75% of their weight per day. Knowing the waste production rate allows you to calculate the right quantity of earthworms for the bin so that the waste you add is consumed on a daily basis. Since worms do not perform well if they are crowded, enough medium should be used to keep them at a density close to 150 worms/litre.

The UFO Earthworm Bin Calculator generates the dimensions of a 2-bin vermicasting system, along with the amount of earthworms and starting medium required to meet the feeding and living needs of Red Wigglers, allowing waste to be consumed as fast as it is produced. A 2-bin system is used so that after 15 days out of a 30-day cycle waste is added to a second bin, which attracts earthworms out of the first bin and separates them from the finished vermicast. The finished product is a rich fertilizer ready to use safely on plants. When it is two weeks of age, most of the ammonium in this material turns to nitrate, a plant’s favorite form of nitrogen, and the level of beneficial microbes increases in it. Even when fresh, vermicast does not have high levels of salts and that makes it safe to use on plants.

Balcony Garden DIY

balcony garden DIY

Balcony gardens provide substantial private and public benefits. A homeowner with a balcony garden should anticipate reduction of noise, improved views, reduction of city pollutants, improved air quality and fresh herbs for cooking. Not much has been written about the public benefits of balcony gardens but one would expect many of the same benefits attributed to rooftop gardens.

A do it yourself balcony project should take a systematic approach that takes into account environmental factors, design processes and practical considerations to arrive at something you really want as part of your living space.

Here are some general guidelines to consider when designing a balcony garden.

Ecology of Balcony Gardens

A conceptual model of a balcony garden would begin by finding a comparable ecosystem to identify plants that will be successful. One example that comes to mind is a rocky outcrop on a cliff.

Many examples of this type of vegetation can be seen growing along highways in sections that have been blasted away and plants are growing on small ledges clinging to life. In some cases moisture is seeping from the cliff face itself, or perhaps the tenacious plants have roots that reach deep into crevices in search of moisture and nutrients.

What plants are successful in this stressful environment? What strategies of survival do they employ to eke out a living? By looking at some of the similarities and differences we can build profile of plants characteristics that enable plants to survive well in a balcony garden situation.

Of course a balcony garden has a human being inside willing and able to bring out water as needed, supply soil, install containers and even bring plants inside for the winter should the need arise. Nevertheless thinking about the defining characteristics of life on a cliff can help to shape our ideas about balcony gardens.


The direction a balcony garden faces is important because it provides a basis for assumptions regarding light conditions and informs appropriate plant choices.

The direction the balcony faces is a determining factor in the quantity and quality of light available for plant growth. North-facing balconies are unlikely to receive direct sunlight for any significant period of time. South-facing balconies should get direct sunlight for a good portion of the day provided there are no other obstructions such as adjacent buildings in the way. East-facing buildings will receive morning light that is less intense than a west-facing balcony facing the full strength of afternoon sun.


The amount of wind that a plant can tolerate is a function of the species in question and the availability of adequate moisture in the root zone.

Plants require water to survive and need additional water if stressed from heat or high winds. Since many balcony gardens rely on small pots it is important to monitor moisture levels and mitigate wind as required. Typically you will need to pay more attention than in a ground garden as the available moisture in containers depletes, it can only be replenished by you (it is important to note if you are getting any rainwater at all as many balcony gardens are not exposed from the top and are in a significant rain shadow).


Although forecasts are given for the city as a whole vast differences can be found especially on rooftop balconies. Localized differences in temperatures are known as microclimate. In general it safe to assume that balcony gardens will experience colder temperatures the higher they are established. Furthermore, expect temperature fluctuations to be more severe if the sun pops out from behind the adjacent building quickly warming the concrete façade. In addition to these air temperature fluctuations, soil in the containers will not warm up like similar gardens in the ground. They will be at further risk of freezing and thawing quickly adding more stress on plants. One way to mitigate this is to insulate containers prior to installing soil media.

Even with all those plants, this gardener still needs protection from hot afternoon sun.


Another important consideration after the environmental observations have been made is human use. Consider the amount of space you have and the types of activities that the space should be able to handle.  Will the garden be strictly ornamental in nature or will it be used for food production? Will you be entertaining in the space? What about pets and children?

It might be easier to start with a spectrum with high use on one end and purely visual with access only for maintenance on the other. Considering functionality will help determine the size, quantity and layout of containers and furniture. You don’t need to be great at drawing to work at the concept level. Think about how many people will typically use the space and the flow of use (if you plan on having tables make sure you have room to pull a chair back to sit down and room for someone to pass behind).

This balcony garden is so small they decided to use the vertical space and leave the horizontal floor space free for other uses (read seating, eating and entertaining).


The balcony garden is made of floorspace, furniture, containers and plants. In some cases irrigation, lighting and bbq’s are additional considerations. Typically balcony gardens are small so purchase what you really like. If you have a larger area you will need to be very careful about your floor covering choices as this will impact the budget significantly.

When making a decision about furniture, consider proportion. I would suggest narrow tables and smaller chairs for really small spaces. Forget about large blocky wicker sofas as it will just look cramped. The exception to this is container size. Containers are expensive and you will pay more for planters that do not need to be emptied out annually. Experienced gardeners can maintain many small pots of interesting plants. If you are just starting out it will be easier to maintain a few large containers than many small individual pots (small pots dry out more quickly).

Another important component is soil media. Most bagged container mixes will be adequate to start, however, it is critical to feed the soil as plants remove nutrients from the soil over time. The nutrients will not be replenished through natural processes. It is up to you to replenish with additional bags of compost or fertilizer.

Plants and Design

Consider the items above prior to plant selection to help create a profile of ideal plant characteristics. This will help to narrow the palette of plants that will do well. Now would be a good time to think about aesthetics. I like to create a collage of the plants I would like to use so I can see how they will look together. This can easily be done directly in the nursery if you take the time. If you really wanted to get fancy you could add samples of the furnishing colours, fabrics and floor to the collage to get a feel for how the plants play off the rest of the balcony furnishings.


Balcony Gardens provide both private and public benefits. It makes sense to tackle them using a systematic approach that looks at environmental factors, design process and practical considerations to arrive at something you really want as part of your living space. Check back for further articles that take on these topics in more detail going forward.

Ideally plants should be integrated into the structure and function of buildings right from the get go. Ultimately buildings are just bones of a body with no skin. For the most part they are built to protect the activities that occur within but fail to exploit all the activity happening outside. How about capturing some free energy, water, wind and on top of that make it aesthetically pleasing too.

at least compared to this…

Balcony Composting

Balcony Composting

Making a balcony composter can be easy. We developed this composter with some ideas found on the web, adding our own modifications.


  • A large planter about 45 cm diameter, with a tray to catch excess water
  • A pail about 27 cm diameter, at least 35 cm tall
  • Potting soil
  • A drill
  • A saw with a narrow blade


  • Cut out the bottom of the pail using the drill and saw. Drill several holes (lots!) in the pail and lid.
  • Cut a little trap door in the bottom of the planter (about 12 cm by 12 cm). This is for removing the finished or near-finished compost from the composter. You might need to use something to keep the trap door shut when not in use.
  • Put 5 – 10 cm of soil in the bottom of the planter. Drop the pail into the centre of the planter. Fill the rest of the planter (around the pail) with soil up to near the top of the planter.
  • For aesthetics, plant some small plants in the ring of soil that surrounds the pail. Also, keep the lid on the pail and perhaps place a smaller planter on top of it.
  • To keep your balcony composter odour-free, stick to these general rules:
    —Do not throw any animal-derived products (meat, egg, dairy, fish…) or oily foods into your composter. Basically, keep it vegan and oil-free.
    —Cut food scraps into small pieces (generally no larger than the size of a quarter coin) to facilitate breakdown.
    —Every time you throw in food scraps, throw in the same volume of dried leaves, and stir everything deeply with a bamboo stick. The drilled holes help with passive aeration, but the stirring is important for aerating the bottom parts. Aerating keeps the composter breaking food down “aerobically”, which doesn’t smell.


  • If your composter smells, it means that it might be too wet, or you’re throwing in foods that shouldn’t go in, or you’re not aerating enough.
  • Fruit flies: After you add food scraps and dried leaves, and after aerating, sprinkle some sand or crumbled dried leaves on top of the compost before closing the lid.

Most of the excess liquid from the composter is absorbed by the surrounding soil in the planter. As the composter gets full, the pail can be lifted a bit higher out of the planter to allow for passive aeration through the drilled holes.

When your composter gets too full, start removing the finished or near-finished compost from the trap door. If the compost is not finished yet, you can leave it in a separate pail for a few months or give it to someone who can pile it in the corner of their garden.

You’ll find that the volume of compost coming out of your composter is only a fraction of the volume of food you put in.

Have fun!

Start Seeds Indoors in Four Simple Steps

seedlings indoor

I can still picture my grandfather fetching a plastic washbasin from the laundry room. We were planting tomato seeds indoors—and didn’t have any trays or pots. It didn’t bother him. He added a few handfuls of potting soil to the basin, tore open the seed packet, casually sprinkled on some seeds, and encouraged me to sprinkle on a few more. We covered them with a bit of soil and were done, except for a label made from masking tape.

That memory conveys what I’d like to share: starting seeds indoors isn’t rocket science.

Let’s break down planting seeds into four simple steps:

1. Soil Meets Container
First of all, a quick note about soil…or lack of it. A soilless mix is a good choice for starting seeds. Such mixes, often made of peat moss, perlite, and vermiculite, are generally free from disease, and allow good movement of air and water around your seedling roots.

Lightly fill your container right to the top with your soilless mix, but don’t compact it. Don’t bother tamping with your hands or a flat object, which many books recommend as a way to remove air pockets. You’re just complicating things. Instead, simply give the filled container a couple hard knocks on the table. This will cause your soilless mix to subside—to sink a bit—leaving you room to add your seeds and some more mix.

2. Seeds Meet Soil
Don’t sweat the spacing of seeds, and definitely don’t buy any seed dispensing gadgets. Usually when we start seeds, it’s in a temporary home—somewhere they can germinate. So a bit more or less space between seeds simply affects how soon we need to transplant the seedling to a larger container.

Hand sprinkle (broadcast) the seeds from the packet onto the soil. Sometimes tapping the seed packet will dispense the seed uniformly. But not always…If seeds are too small for hand sprinkling or dispensing from the packet, try this: Place seed in the fold of a piece of folded paper. Then, tap the paper or use a pointed object (a finishing nail works well) to move the seed from the paper onto the soil.

3. Covering Your Tracks
Now we cover the seeds with soilless mix (2-3 times the width of the seed.) Some gardeners cover seeds with fine vermiculite or sand, which, with a finer texture, can be easier for germinating seeds to poke through. I find soilless mix works just fine and don’t bother with these additional supplies. At this point, tap your container again to remove air pockets. In most cases, very fine seed can be lightly pressed into the surface of the soilless mix instead of being covered.

4. Water, Cover, and Wait
Now it’s time to water, and you have choices. You can (1) use a watering can (gently, so as not to wash away seeds); or (2) water from the bottom by setting the container in a couple inches of water (the water will wick upwards) for a couple hours.

With seeds planted and watered, cover them to keep them moist. Use a plastic dome or clear plastic bag. Check daily for moisture and for germination. BE PATIENT. Germination takes anywhere from a couple days to almost a month, depending on what you’re growing and the temperature.

Vegetables and Herbs to Grow on Balconies

Vegetables and Herbs to Grow on Balconies

The following vegetables and herbs will grow well on balconies.

Container balcony gardening is very different from regular gardening in a few key ways:

  • There is less soil available to the plants and less space for them to grow in. Plants only grow as large as their roots are allowed to spread. The larger the plant the more its roots need to spread. And you don’t want your plants spreading all over your balcony.
  • It’s a drier environment for the plants. The soil in containers dries out more quickly than in the ground since the walls of the container are exposed to air and light.
  • Balcony gardens tend to have windier environments. Often there is a lot of sun with little shade.
  • Also, since the balcony garden does not lend itself to overwintering herbs, best to stick with annual varieties.
  • So…plants that do better in containers on balconies tend to be those that have contained growth and those that can handle more adverse growing conditions.

Most herbs fit these criteria since they like loads of sun and are pretty drought-tolerant. Particular ones would include basil (all varieties), German Chamomile, cilantro, parsley, salad burnet, summer savoury, sweet marjoram and summer thyme.

Veggie varieties that are better candidates for containers include: bush beans (pole, if you can add poles); beets; Little Finger carrot; Little Fingers eggplant; most greens – lettuce, Dwarf Blue Curled Scotch Kale, mustard greens, cress, purslane, collards; onions; Dwarf Grey Sugar Pea; most peppers, although some, like Tollie’s, Aurora and Nosegay are very small and can be grown in the smallest containers; Red Malabar spinach (if trellised). Galilee spinach; radishes; swiss chard; turnips; tomatoes – determinate* ones only, such as Black Sea Man, Red Burbank, Nebraska Wedding. (*Note: determinate tomatoes stop growing at about 3 feet; indeterminate tomatoes keep growing until they reach 6 feet or so and would be unwieldy for a balcony).

For vegetables, it is important to use the right-sized containers. Root crops like beets, carrots, radishes and turnips need deeper containers according to how deep the roots grow. Tomatoes grow larger than herbs so would need larger containers that hold more soil. This is because the larger the plant is, generally, the more nourishment it needs and, since it draws its nourishment from the soil, the more soil it needs to draw from.


Join Toronto Balconies Bloom, Riverdale Food Working Group and Toronto Green Community for our 2012 Edible Garden Container Photo Contest! Let’s showcase Toronto’s wonderful small space gardens and inspire the multitude of container gardeners to get creative! Anyone growing any kind of edible plant in a creative container is invited to participate. All are welcome, beginner to experienced – no garden too weedy, no container too small!

Compete for great prizes!

Photos will be judged by celebrity gardeners. Prizes will be awarded based on criteria such as creativity (handmade items), innovation (ingenious use of materials), aesthetic value, plant vitality and plant design. Winning submissions will be showcased on the Toronto Balconies Bloom website.

Want to participate? Here are the guidelines:

  • 75% of the plant material must be edible (vegetables, fruit, herbs, edible flowers).
  • Containers must be salvaged, recycled, reused, reusable, DIY or handcrafted.
  • Submit 2 photos — one close-up of your crop-in-a-pot and one that includes its surrounding. Please include your name and a brief statement to introduce your creation to the judges.
  • Recommended photo specs: 500 pixel minimum width and 72 dpi resolution

Any new information will be posted here on the TBB website.