How to Space Vegetables in a Raised Bed

Whether you’re growing vegetables in a traditional in-ground bed or a raised garden bed, the importance of the right spacing cannot be overstated. Growing too many vegetables in too small a plot can lead to a poorer yield. 

There’s a range of different ways to space your vegetables to ensure you’re making the most of every square foot you’ve got available. 

Why is Vegetable Spacing Important? 

Appropriate spacing for your vegetables is important for a number of reasons. 

All plants require space to spread their roots. When grown too close together, root growth will slow, and a range of health problems can start to develop. 

Nutrient Deficiency

One of the main issues you will see when vegetables are grown too close together in garden beds is a nutrient deficiency. 

This is because vegetables need to compete with each other for soil nutrients. Too many plants in too small an amount of soil will leave some without enough, as the nutrients are used up quicker. 

While fertilising and feeding can prevent nutrient deficiency, this will considerably add to the amount of work needed to maintain your raised beds. Instead, it’s better to adequately space the plants, and ensure they are planted in a nutrient-rich soil.

Weak foliage, poor growth and failing to fruit are a few symptoms of nutrient deficiency, which may indicate too many plants in a too small area.

Increased Risk of Disease

Vegetables that are too close together will receive poor air circulation, which can lead to fungal diseases as the leaves get damp.

When the leaves are very close together, it’s easy for pests to travel in between the plants. If one plant has aphids or mites, it won’t be long before the others do too.

When your plants are correctly spaced, air can travel in between the leaves and dry them, preventing diseases that stem from damp conditions. 

Poor Flowering

If your plants aren’t flowering or fruiting, it could be because the lower leaves aren’t receiving adequate sunlight, moisture or nutrients. 

It could also be that the roots aren’t able to spread out, meaning they’re unable to extract sufficient nutrients from the soil. 

More Likely to Dry Out

If your vegetables are planted too close together, your beds will dry out quicker. This is because there may not be enough water in the soil for all the plants, so the vegetables are competing for what there is. 

As a result, you’ll need to water your beds more often to maintain the moisture levels. 

Not only that, watering can also be more difficult. This is because the plants cover the soil more densely, so it’s harder to get the water right into the ground. Instead, you may end up simply soaking the foliage which, if there’s not adequate air circulation, can lead to fungal diseases.

How Much Space Do Vegetables Need? 

There’s a balance to strike between giving your vegetables enough space and being space efficient. One of the best things about a raised bed garden is that they allow you to plant more within a smaller area, making them suitable for those with a small garden.

There’s a variety of vegetables that are happy to be grown close together in a smaller space, needing just a couple of inches of space between them. Larger, slower growing vegetables may prefer a couple of feet of space between them.

As a rule of thumb: 

• Carrots, onions, peas, and radishes prefer to have around 2” to 3” of space between them.
• Beetroot, garlic, leek, spinach and turnips require between 4” and 6” of space between them. 
• Celery, lettuce and chard require between 7” to 9” of space between them. 
• Tomatoes need around 12” of space on all sides. 
• Peppers, potatoes, cabbages, broccoli and cauliflower require roughly 15” to 18” of space. 
• Larger vegetables such as aubergine, squash and melons require up to 24″ of space.

Some vegetables are best planted in traditional beds, as they are hard to plant efficiently in raised beds because they need so much space. 

If you’re unsure, the seed packet will say on the back how much space the seeds need, as well as information about the soil pH, seed sowing depth and sunlight requirements. 

How to Grow More Efficiently

Carefully Select your Seeds

If space is at a premium and you’re wanting to grow as efficiently as possible, the first step is to select the right seeds. 

You may need to sacrifice the squash or pumpkins in favour of smaller vegetables that take up less space, such as carrots and onions.

Increase Surface Area by Mounding

The length and width of your raised beds are important, but remember that you can also plant vertically. 

This is known as ‘mounding’, and involves increasing the depth of your bed.

An example of this is when growing potatoes. As they grow, mound more compost around them. This will produce more surface area for the potatoes, but you won’t need to dig any deeper into the soil. 

Consider Square Foot Gardening

Another gardening method that can be used to increase the amount of space you have available is known as ‘square foot gardening’.

Invented by Mel Bartholomew, this form of gardening is structured and highly organised.

The concept is very simple. Your raised beds should measure 4 ft x 4 ft, and each bed should contain 12″ x 12” x 12” squares. Each bed should measure 16 square feet.

Each square is individually managed, containing one large plant or, if you are planting smaller vegetables, these squares can be further divided. For instance, you could divide one square into 16 smaller squares, and plant 16 individual radishes (as these don’t require a lot of space).

This method of gardening offers a number of advantages. Higher yields, more fertile soil, less labour and easier pest control make square foot gardening arguably the best way to manage growing a lot of produce in a small garden area.

Pros of Square Foot Gardening 

This method makes the most of available space, and allows you to monitor each plant individually. It can lead to higher yields, better space efficiency and lower maintenance.

By ensuring each vegetable has a certain amount of space, you are very unlikely to overcrowd the bed, but you’ll still be able to use the space very efficiently. 

Cons of Square Foot Gardening 

There’s a few things to bear in mind when it comes to this method of gardening. 

The first is that building raised beds and purchasing dividers can work out costly. 

Another is that plants which take up a lot of room (for instance winter squash, asparagus or corn) are still unlikely to have enough space in a 12” grid. This method is best for more compact veggies. 

The recommended depth is 6” which is too shallow for most veggies. Instead, you’ll need a depth of at least 12”. 

Trellis Planting

Another easy way to add more growing space to a raised bed is to plant in trellises. This involves training plants to grow vertically instead of on the ground, which has the added benefit of reducing soil-borne diseases. 

You’ve probably seen tomatoes growing on trellises before, but you can also try it with beans, cucumbers and squash. If you’ve got an area of your garden that’s overlooked, creating trellises can help screen certain areas. 

Companion Planting

Another way to maximise space is to plant specific vegetables that are compatible together. This way, they can be planted closer together, giving you a higher yield in the same amount of space. 

This works because hardier plants can protect and shield the more delicate varieties, providing protection from the elements. Some plants also release essential nutrients into the soil, ready for their next door neighbour to enjoy!

If you’re growing edible produce, companion planting can actually improve the flavour of what you’re growing. Thyme for instance, is said to enhance the flavour of strawberries when planted nearby. 

Let’s take a look at some plants that can be planted in the same beds.

• Tomatoes, onions and basil
• Cabbage and radishes
• Lettuce, carrots and chives
• Squash, runner beans and corn

Remember that some plants are not compatible, and growing them close together can lead to a poorer yield. Vegetables which are from the same family are sometimes best grown apart to prevent cross-pollination.

Plants to keep separated include: 

• Garlic and peas
• Carrots and dill
• Cucumbers and any fragrant herb
• Broccoli / cauliflower and peppers, squash or strawberries
• Potatoes and anything! 

You should also check that whatever you are planting together is roughly the same size. 

Taller plants like tomatoes for instance can cast shade on the other plants in the bed. Ensure these plants will still get enough sun even as the tomato plants grow. 

Raised Bed Vegetable Garden FAQ

What vegetables are best in a raised bed?

Most vegetables will do well in a raised bed, with those that are too large the only vegetables that may struggle. 

Some of the best vegetables for beginner gardeners to grow in their raised garden include: 

• Radishes
• Onions
• Spinach
• Carrots
• Rocket
• Tomatoes

What vegetables should not be grown in a raised bed? 

Vegetables that either take up too much space, have too large a root system or take too long to grow are best grown in traditional in-ground beds as opposed to raised beds. 

Examples include asparagus, corn, broccoli, squash and cauliflower. 

While these can still be grown in raised beds, they aren’t particularly space efficient. 

How deep should a raised vegetable garden be? 

The amount of space your plants have vertically is just as important as the amount of space they have surrounding them.

It’s recommended that, for growing vegetables, your beds are at least 12” deep. 

Tomatoes, cucumbers, courgettes and kale require around 24” of vertical space for their root systems. 

Lettuce, carrots, radishes and peppers require around 12 inches of soil for their root systems.