Balcony Garden

(Question)

Hello, I live in Toronto and have a very large balcony (5′ x 20′) that I am determined to make into a successful garden. Unfortunately, last summer was my first year attempting to garden, and I made some mistakes that cost a lot of plant lives and yielded only a few herb plants and about a handful of cherry tomatoes.

I have since done lots of reading, research and planning but am still nervous about some of the factors that I will be working against. My biggest concern is the sun. My balcony is WWN facing and it is set into the building (oppose to overhanging) with a solid concrete ledge so the sun doesn’t shine into the balcony until mid to late afternoon when it is it’s hottest. I’m concerned that even with the largest pots and proper watering the sun will still be too hot for even the most sun loving vegetables and flowers? I know last year I had too small of pots for my tomatoes (and pots with no drainage for other plants) but I’m wondering if a larger pot with drainage (= more moisture) would be enough to go against the hot sun. I have been thinking if I will need to try to filter the light to reduce the severity of it.

I think the majority of my issues stemmed from this hot sun + small pots but reading through some of the other questions, would pollination affect the yield of the vegetables as well? I am on the 18th story and even if I plant pollinators (and they successfully grow) I’m not sure they would be enough to attract anything up to my balcony… would this have a large impact on the plants?

Additional info: basic potting mix used from garden centre for all of the plants, sometimes would be very windy on the balcony, I didn’t fertilize anything.., if I was gone for a longer period of time I would move my plants indoors to be in less direct sunlight and reduced heat (minimal to no a.c. but cooler environment), even though the pots were smaller I did water them every day and they rarely got too dry.

Thank you and I hope this is enough info, any and all tips are extremely appreciated!

Kindest regards,
Wannabe Master Gardener

(Answer)

Thank you for contacting Toronto Master Gardeners.

From your description your plants have to fight against  heat accumulation into your concrete balcony. Plants next to concrete that absorbs and radiate heat may be hit with temperatures higher than the thermometer says.

Choose your material carefully. Large containers slowly dry out. Plastic pots hold moisture more effectively than porous terra-cotta. Use light-colored pots that reflect sunlight and absorb less heat.

The main defense plants have against high temperature is water. Plants cool themselves by allowing water to evaporate from their leaves.  Set potted vegetables in shallow trays of gravel or clay granules. Water that drains through the pots evaporates slowly from the trays, cooling the surrounding area and increasing humidity around your container garden vegetables.

Containers dry out quickly and will need to be watered every day. To save time, money and water, or if you plan to be away from your garden for an extended period, consider installing a drip irrigation system. Drip irrigation systems apply water in a slow, steady trickle and reduces the amount of water lost to evaporation.

A light-colored mulch will insulate the soil and help to to hold moisture.

Plants in containers have limited access to nutrients. Plants that are heavy feeders such as tomatoes will definitely need to be fertilized over the course of growing season. Organic fertilizers are slow release and don’t leach out too quickly.

Hand pollination could be a good way to enhance your fruit production. There are many tutorials on the web to learn. This one explains how to Hand Pollinate Cucumbers and Tomatoes.

Good luck !