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Growing Vegetables in Containers

Thursday, 11 April 2019  |  SimplySeed

What Types of Vegetables Can be Grown in Containers?

Not everyone has a large garden, an allotment, a vegetable plot or any spare room in the garden to grow a few vegetables. Many small town house properties have no gardens whatsoever and if you live above ground level then you might think it’s impossible to grow anything for the kitchen table.

That doesn’t mean you can’t still have a few home-grown, fresh vegetables when you want them. It just takes a little thought, imagination and ingenuity to make the most of whatever space you might have, be that a concrete path, patio, decking, balcony or even a window box. If you have room for a pot or container of any size then there is nothing to stop you from having a go at growing your own food, albeit with some limitations, throughout all of the summer months.

 

What types of containers can be used for growing vegetables?

If you were to wander around a garden centre then you might see hundreds of different types of containers, from 5cm plastic pots to 100cm Grecian style concrete urns. There are many ornamental types of containers but the humble vegetable is not really going to be too concerned about the style, shape and colour of their container, as long as it suits their needs.

That said, you can generally look much closer to home for containers that will do the job just as good as the most expensive stoneware or terracotta pots. Many are very low cost and even free. All that is required of a container is that it can hold a sufficient amount of soil and has an adequate means of drainage. So let’s look at the options…

Pot – When we think of a plant pot we generally think of the traditional black or tan coloured plastic plant pot but the term “pot” can cover a multitude of options. For example, an old aluminium cooking pot or a cauldron, or any metal, cast iron or earthenware pot including a ceramic pot and even a chamber pot.

Planter – This is another broad term and could include a wooden box, a plastic crate or a window box. In fact, anyone with a little knowledge of woodwork could easily make a wooden planter. Basically, a planter is any type of container that can be filled with soil, compost and plants. A potato planter, a chimney pot, any type of basket and even a section of plastic rainwater pipe can qualify as a planter.

Raised bed – A raised bed is a container that has been constructed from timber, bricks, blocks, concrete or plastic panels. It’s usually a purpose-built container but would generally need more room than most other containers and cannot be moved around easily, if at all.

Hessian sack – Hessian sacking has been used commercially in horticulture since the 1950s and before that was used, and still is used, to package many types of products including coffee beans. It’s also still used for tree root balling and as carpet backing. Made from natural Jute, hessian is biodegradable, it’s cheap and very easy to use for growing vegetables.

Trough – an example of a trough might include a long narrow wooden or metal structure and even an old kitchen sink. A window box is a kind of trough. A trough is ideal for placing adjacent to a footpath or to one side, or on several sides, of a patio area.

Bin – Any type of bin from a peddle bin to a dustbin or a bucket or barrel are suitable containers for growing vegetables. A full oil drum or a half oil drum and an old water butt will also suffice. Industrial cooking oil drums also make good containers as do plastic bins used for home brewing, which are very easy to source and cost very little. Many plastic bins are often discarded at waste collection centres.

Growbag – There is, of course, the typical purpose-made growbag complete with growing medium but also, any plastic bag or shopping bag can be transformed into a grow bag. Bin liners, especially the strong black dustbin type are perfect for creating homemade growbags.

 

Preparing your container for vegetable growing

Whatever type of container you decide to use for your vegetable growing, it’s vital that you start out with a clean and safe planting vessel. Ensure all remains of any detergent, chemical or oil has been completely removed by washing thoroughly with a jet of water. If you have to cut and remove the top of the container to make it wider then ensure there are no sharp edges. If sharp edges are exposed then tape them over or cover the exposed edges around the rim with cloth to prevent any accidental injury.

All containers must have drain holes to allow excess water to drain away. In most cases, you will need to drill these holes so take care when drilling or puncturing the base with some other sharp implement. Hollow tubes, such as drainage pipes, make good containers and can be set into large plant pots or pushed into the ground.

 

Getting the growing medium right for best results

Next, you will need to add some suitable compost or soil to your container. Most vegetables will grow best in a loamy type soil that holds moisture but drains well. All vegetables need an ample supply of nutrients in order to grow quickly and healthily. Known as the Big 3, Nitrogen, Phosphorous and Potassium (NPK) are essential for good plant health. Most leafy type vegetables such as cabbage need more nitrogen, whilst flowering types such as cauliflower and calabrese need more phosphorous and potassium, which also helps to develop a healthy root system. Most standard multi -purpose composts contain some nutrients but with the addition of a general, slow release NPK fertiliser, plants will grow much stronger.

Alternatively, you can opt for an organic vegetable compost, which should contain all the right ingredients in the exact quantities. If you have access to well-rotted organic matter then this can be mixed together with most types of compost to add more body and to provide natural plant food. Another consideration is the pH of the soil. Some vegetables, such as potatoes, much prefer and will grow better in an acidic type soil, which has a pH value of less than 5.5. Other vegetables such as cabbages, broccoli and cauliflower prefer a pH value of around 6.5. Many pre-packed, commercially available composts will display the pH value on the bag.     

 

What types of vegetables can you grow?

Lettuce - Let’s start with salad type vegetables, as generally, they are quicker and easier to grow than most others. Lettuce is probably considered a vital ingredient of any salad and thankfully it’s extremely easy to grow. A single lettuce plant will grow quite happily in a 10cm diameter pot and needs a depth of at least 10cm. So long as it gets plenty of water and has all the nutrients it needs, it will grow big enough to fill your salad plate with fresh, crisp and tasty leaves. The cut and come again varieties, often known as “salad leaves” are well worth considering because you can get so much more value from a few young plants that are never allowed to fully mature.

Tomatoes - Tomato plants will grow well in pots and other types of containers but they need much more room. For example, a minimum 25cm size pot or about 10 litres by volume of compost is required. If you are growing your tomatoes outdoors then stop them at 4-5 trusses to give them a chance to fully mature. They will also need some support. Alternatively, grow outdoor bush tomatoes, which are smaller but much more prolific and don’t need quite as much attention.

Cucumbers - Cucumbers too can be grown in containers and again a minimum size pot or container should be 25cm for one plant. You will need to stake cucumbers with canes or otherwise support the plants as they grow. Many potato planters, barrels and large dustbins are suitable for growing several cucumber plants.

Onions - Onions can be grown from seeds or from sets and will grow fine in a container, as long as they have enough room to mature. The closer you space your plants, the smaller the onions will be. A minimum pot size of 15cm diameter and 15cm deep is required for individual onion plants or space them at 10cm -12cm in larger containers. Planting onion sets will give you a head start over seeds and you can, of course, harvest your onions whenever they have reached a size that is considered suitable.

Carrots - The carrot is a very useful vegetable. It is basically a tap root and therefore needs a deep container of at least 30cm. They can be grown in groups spaced at 7.5cm apart or in individual pipes or tubes, depending on your available space. Large tubs, bins and buckets are ideal for growing small crops of carrots.

Cabbage - All types of cabbages and even Kale will grow perfectly well in a container as long as the compost is right and there is sufficient space for them to mature. Your typical cabbage will need to be spaced at a minimum of 30cm apart. This will produce smaller head cabbages. For much larger heads increase the spacing to 60cm. If you intend to grow cabbages singularly in pots then ideally you will need a container with a capacity of 7.5 litres per plant.

Cauliflower – Sprouting Broccoli and Calabrese, like the cabbage, will need to a lot of room to grow so a minimum container size with a capacity of at least 7.5 litres and preferably 45cm in diameter will produce reasonable size plants and heads. Cauliflowers will grow best in a moderate to cool position and although they do need around 6 hours of sun each day, take care not to expose your plants to extremes of heat. Summer, autumn and winter varieties are available.

Spinach – Spinach is relatively easy to grow in all types of containers. It’s a versatile leafy vegetable that can be continually harvested on a cut and come again basis. There are summer and winter varieties available, providing fresh tasty spinach all year round. Spinach can be grown as individual plants in 15cm wide pots or planted in groups in larger containers spaced at 20cm - 30cm apart.

Radishes - Radishes are very useful vegetables, which can be used raw in salads or roasted to accompany many other dishes. They are very easy to grow in containers and don’t need much room to mature. They will grow in individual pots, size 10cm to 15cm, or can be grown in groups of 4-5 in containers with a 10 litre capacity. 

Peas - You will need individual pots of at least 30cm diameter per plant or plant groups into containers and space at least 45cm apart. Peas will need supporting with either canes and netting or “pea sticks”. If you grow the dwarf or shorter varieties then you will only need containers or pots with a depth of around 15cm and a diameter of 15cm to 20cm. If growing in groups then space the plants at 10cm apart.

Beans - Runner beans will need deep pots or containers of at least 30cm and some sturdy supports. It’s best to grow runner beans in heavy containers so that they don’t blow over in the wind. French beans only grow to around 30cm to 40cm high so will generally not need supporting. Both are very easy to grow.

Peppers & Chillies - All types of peppers and chillies can be grown in pots and look very decorative if placed around the patio or alongside a footpath. They are very easy to grow in pots and will do well in a single pot size of 20cm or spaced at 20cm apart in larger containers. Chillies will very happily grow in a 1 litre pot placed on a sunny window sill.

Chard - Chard, often better known as Swiss chard is another relatively easy plant to grow in containers. One plant will grow in a 20cm diameter pot although 30cm diameter is better. If growing in larger containers then space the plants at around 15cm to 20cm apart. Chard looks very decorative with striking red or yellow stems and would not be out of place on the edge of a patio.

Marrows & Squashes - Including gourds, pumpkins and courgettes can all be grown in containers with areas of 45cm spacing all round for the larger pumpkins and marrows. A 20-30 litre container will be required for one pumpkin or marrow, 3-4 gourds or 4-5 courgettes. Grow bags are ideal for growing all types of squashes but remember that some plants will trail so the growing “fruits” may need some vertical support or at least be supported as they grow along the ground to prevent damage to the skins. 

Potatoes - Most cooked meals are served with potatoes and this vegetable forms a major part of our staple diet. It’s no wonder then that it’s a very popular choice for growing in all types of containers by the majority of limited space gardeners. Potatoes do need a lot of room to grow and for that reason, you will need very deep containers such as buckets, bins, drums or deep bags. You can buy purpose made potato planters, which have a removable section at the bottom so you can harvest your crop quickly and easily. You have a choice of planting earlies, second earlies or main crop potatoes or all three if you have enough containers.

Place the seed potatoes 30cm to 45cm apart in containers that have a depth of at least 45cm to 60cm. You will need to start at about half depth of the container and then add 10cm of soil regularly as the plants grow until you reach the top of the container. As a general rule, each potato plant will need about 10 litres of loamy compost. Growing potatoes do take a little bit of work but are well worth the effort.

 

Some things to remember when growing vegetables in containers

Containers are much more likely to dry out quicker than soil beds so plants in containers may need more frequent watering, along with applying a regular liquid feed. Some things to bear in mind when growing vegetables in containers are the size of the actual container and how close the plants are positioned, will very often limit the size of the full-grown plant and ultimately the size of the resulting vegetable. So basically, a small pot will produce a small vegetable. But if space is at a premium then perhaps it’s better to grow a series of smaller vegetables than none at all. Have fun experimenting with growing all types of vegetables in all types of containers.