Container Gardening (Mitchell Beazley, 2013) by Ian Hodgson offers advice on creating impressive partnerships of pots and plants for every style of container and every size of garden. The following excerpt from “Crops in Containers” shows you how to navigate container choices and choose the best vegetable crops to grow for optimal vegetable container gardening.
You can purchase this book from the Mother Earth Living store: Container Gardening.
Vegetables in Pots
Some vegetables have long been associated with container cultivation, particularly those tender crops generally grown in glasshouses in cool-temperate areas, such as tomatoes, cucumbers, melons, peppers and aubergine. Here, breeders have produced cultivars that are more compact and more durable for cultivation outdoors in often fickle summers; the plants are also resistant to the devastating diseases they are likely to encounter when grown outdoors.
Other vegetable crops are idea for pot culture for the following reasons:
• They are standard cultivars, but can be harvested when young or immature.
• The height/proportions of the plant have been reduced so it is more manageable in a pot or small space.
The type of container required will depend on the vegetable you want to grow, whether it is a taprooted crop (such as carrots), a leafy salad crop (such as lettuces) or a shrubby or climbing plant (such as peppers, tomatoes or cucumbers). You may also want your vegetables to become a feature in themselves. Many have attractive flowers, leaves or fruit and can be collectively grown for display. If long-lived, such as rainbow-leaved chard, the vegetable can be used as an incidental element with other ornamental plants. In this instance you will want an aesthetically attractive container, such as a terracotta urn, molded plastic tub or timber crib or planter, rather than a purely functional growing bag, black plastic pot or recycled container.
Planning Your Crops
Vegetables have different rates of growth, and, depending on whether they are harvested for their roots, stems, leaves or fruit, these will determine how and when they should be grown. The way plants produce their edible parts is also influential. Some crops can be selectively picked over a period of time, while others are completely removed when mature. For example, tomatoes and cucumbers are grown for the whole summer and their fruit picked as it ripens; Swiss chard leaves, too, are removed as required, while hearting lettuces are usually harvested in their entirety before they bolt.
It is essential you plan your vegetable campaign in advance to help ensure you maximize the yield from your various containers and maintain continuity of cropping, particularly if you want to mix various vegetables together. The good news about container cultivation is that you don’t have to worry about growing in a rotation, that is, you do not need to change the position of various vegetable types each year as you would in open ground, to prevent the build-up of damaging pests and diseases.
Ensure you use fresh potting compost in your containers each year. After you have finished, place old, spent compost on the compost heap or dig it into the ground as soil conditioner:
The easiest method of growing vegetables is to have just one type of crop per container, be it lettuces, beetroot or carrots. Here you can provide perfect conditions for the crop and replace it with another once it has been harvested.
With a little ingenuity, you can mix tall crops with shorter or more compact types: for example, you could have a tomato or cucumber in the centre and underplant this with various salad plants or baby beetroot. Later crops, such as runner beans, planted out in early summer, could be preceded by a catch crop of radishes or spring onions.
If you require a plantation of a vegetable such as dwarf French beans or dwarf peas, use a woven fabric vegetable planter, as it combines a good surface area in which to plant with appropriate depth for the roots.
While you should always grow crops for their flavor or other culinary qualities, where possible select those cultivars that have been bred in your own country as they will better withstand any variable weather and particular diseases. An ever-widening selection of tomatoes, cucumbers, aubergines and sweet peppers can now be purchased as young plants grafted on rootstocks that are tolerant of colder soil and conditions than previously; these also offer resistance to soil-borne diseases. This enables plants to establish quickly and start growth and cropping earlier, particularly outdoors. Cropping is further extended into autumn, when conditions start to cool once again.
Both tomatoes and potatoes are being bred for improved resistance to late blight, which in warm, humid summers can devastate crops.
To give their best results, vegetable crops require consistency in the quality of their growing conditions. Place your containers in as sheltered a position as possible, but where they will receive good light for a large portion of the day. Avoid areas exposed to strong or cold winds, which will check growth and cause damage to the plants.
Clustering crop containers together helps provide protection, creating a microclimate of humid air and mutual shade, as well as the convenience of having plants all in one place.
Crops such as tomatoes, aubergines, sweet peppers and chili peppers require bright sunshine to ripen swelling fruit and improve flavor and sweetness. If located in a hot position, do not allow plants to dry out. In severe conditions, such as burning sun or torrential rain, shade crops with a sheet of horticultural fleece to prevent damage.
Keep plants event moist because unbalanced conditions of drought and waterlogging affects performance and causes uneven ripening and physical damage to fruit crops, like tomatoes and sweet peppers.
Feed leafy salad crops and young fruit crops every week with liquid nitrogen fertilizer. Once fruit crops start to flower, change to high-potash liquid fertilizer, such as tomato food.
Vine-like crops require support. Tomatoes can be tied to stout bamboo canes, while twining climbers, such as cucumbers, runner beans, peas and mangetout, need more elaborate support systems. For a single cucumber you could use trellis supported by a cane, or for multiple plants create a tepee of canes, which fit inside the pot rim. Shorter varieties of peas can be encouraged to clamber over short lengths of brushwood inserted between the plans. Climbing crops in pots can also be trained up trellis or sweet-pea netting attached to a wall or fence.
To maximize the space why not combine different types of climber? Mixing together varieties of beans with different flower colours makes a very attractive feature, especially if you want to include a sweet pea or two as well.
Reprinted with permission from Container Gardening by Ian Hodgson, garden writer and designer, former editor of The Garden and editor-in-chief of RHS journals for 18 years. Published by Mitchell Beazley, 2013. Buy this book from our store: Container Gardening.