Growing edibles in containers is a bit different than growing ornamentals. In order to have a successful harvest, most food plants need to do more than just survive, they need to have optimal growing conditions that support the development of perfectly ripened produce. You may be able to grow an heirloom tomato plant in a pot, for example, but that doesn't mean it will produce the top quality tomatoes you're dreaming of.
Potted plants have a restricted root area that creates an inherent disadvantage, especially for plants that want to sprawl, like many vegetables do. They are also prone to drying out in a single hot afternoon (potting soil dries out very fast compared to real soil). Even if you get home in the evening and revive them with a drink, the short term stress is enough to prevent a fruit or vegetable from reaching its prime state of edibility. Greens become bitter, fruits fall off before they ripen, and root crops remain skimpy and tough.
Using containers of sufficient size and watering and fertilizing consistently are keys to growing delicious crops in containers, but there are also certain varieties of fruits, herbs, and vegetables that are much more forgiving of container culture than others. Here are some of the top edibles that are most adapted to planters and pots, so you can have the mini-garden of your dreams on your patio, balcony, deck, or window sill.
The larger the tomato, the longer it needs to ripen its fruit and the more room there is for something to go wrong. Fungal diseases are a huge issue with tomatoes and they tend to develop late in the season as the crop matures. Tiny, cherry-sized tomatoes get around this conundrum by ripening in as little as sixty days from the seedling stage. Cherry tomatoes are more disease resistant than their large cousins and the plants are smaller in overall stature, so they fit easily in a pot. Look for ultra-compact cherry tomato varieties, like 'Tiny Tim', 'Cherry Punch', and 'Baby Boomer'. They are all great for popping in your mouth fresh or dicing up to add zing to a salad.
Most greens are very temperamental when grown in a pot and may not mature with the sweet succulent taste you're expecting. Arugula, a tangy, mildly spicy green, is a different animal however. The leaves retain their gourmet flavor even when the plant starts to go to seed and become very bitter. For most greens, this happens as soon as temperatures hit 85 degrees for more than a few consecutive days. Patios, balconies and decks are like heat traps compared to a vegetable plot out in the yard, making it very difficult to grow tender greens like lettuce. Arugula will send up flower stalks very quickly in warm weather, but you can continue to harvest it and enjoy the greens just the same. Keep sewing a fresh batch of arugula every few weeks throughout the growing season, so you always have some to harvest.
Fruit is notoriously difficult to grow in containers, but there are some exceptions. In response to the huge interest in edible container gardens, plant breeders have developed a number of berry plants that are genetically suited to container culture. There are several tough, compact blueberry varieties that are routinely grown with great success in containers and have also been bred for their ornamental qualities, so your patio garden not only tastes good, but also looks good. Many of the so-called 'patio' blueberries keep their leaves year-round, unlike most others which are deciduous. They are all in the 2 to 4 foot range, rather than the 6-foot behemoth bushes that are normally planted in the ground. 'Sunshine Blue' and 'Peach Sorbet' are good choices for warm climates, while 'Top Hat' and 'Northsky' are better choices for colder climates.
Dwarf Cane Fruits (Raspberries and Blackberries)
Raspberries and blackberries are not difficult to grow in the ground, where they can sprawl as they please. Collectively known as cane fruits, these berries have shallow root systems that like to spread wide, rather than grow straight down, making it difficult for them to adapt to a round pot. Most also have floppy, vine-like canes, that require a trellis and tend to look very messy. Then there are the thorns to deal with - not necessarily plants you want growing in close proximity to your patio hang-out spot! However, a few dwarf, thornless, and free-standing cane fruits are available, which have been bred with container culture in mind. For example, 'Raspberry Shortcake' is a raspberry that grows just 2 to 3 feet tall. 'Triple Crown' is the best blackberry for this purpose, growing just 4 feet tall and wide.
Basil, dill, and cilantro are all very small annual herbs that don't take up much space in a container garden, but like lettuce, they tend to 'bolt' (send up seed stalks) very quickly if they are not kept cool and moist every day of their lives - which can be hard to achieve in a container garden. However, perennial herbs - rosemary, sage, lavender, thyme, oregano and marjoram - live year after year and are renowned for their ability to thrive in containers. These are all Mediterranean herbs, which grow naturally in dry, rocky, infertile soil. In humid climates, they are often healthier and longer lived when grown in containers. They are prone to fungal diseases when grown in the ground in constantly moist soil. In fact, their flavor is more concentrated when they are grown with just enough water to keep them alive - perfect for a hot, sunny spot in your container garden.