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Got a compact metal planter box or a shallow raised bed on your patio? You don’t need a massive allotment or deep trenches of soil to grow your own food.
While deep-rooting crops like maincrop potatoes or parsnips are out of the question, plenty of high-yielding, delicious vegetables thrive in as little as 15 to 20 cm of compost.
If you are working with limited space, these five vegetables will give you the biggest harvest for your footprint.
- Mixed Salad Leaves (Baby Leaf Lettuce)
Salad leaves are the undisputed kings of shallow-container gardening. Because their root systems are incredibly fibrous and surface-level, they don’t care how shallow your planter is.
Why it’s perfect: You can use the “cut-and-come-again” method. Instead of pulling up the whole plant, just snip the outer leaves, and they will grow back for three or four separate harvests.
Top Tip: Sow a small handful of seeds every two weeks to ensure a continuous supply from spring right through to autumn.
- Radishes
Radishes are lightning-fast. Most varieties go from seed to your salad bowl in just 3 to 4 weeks, and because they grow right at the surface, they need very little soil depth.
Why it’s perfect: They are virtually foolproof, making them ideal if you’re new to growing your own food.
Top Tip: Look for the ‘French Breakfast’ variety—they grow in an elongated shape rather than a perfect round bulb, making them even better suited for shallow troughs.
- Spring Onions (Scallions)
Spring onions grow vertically and have incredibly compact roots, meaning you can pack a lot of them into a tight space without them fighting for room.
Why it’s perfect: They take up almost no physical space but add massive flavour to your summer cooking.
Top Tip: When you harvest them, don’t pull the roots out. Snip them off just above the soil line, and the bulb will often sprout a second green onion for you.
- Chantenay Carrots
You might think carrots are off the menu in a shallow planter, but standard long carrots are the only ones that struggle. Short, stump-rooted varieties thrive in shallow spaces.
Why it’s perfect: ‘Chantenay’ or ‘Paris Market’ carrots only grow to about 10 to 12 cm long, giving them plenty of clearance in a standard patio raised bed.
Top Tip: Growing carrots in an elevated planter actually protects them from the dreaded carrot fly, which usually flies low to the ground (under 1 metre)!
- Spinach
Similar to salad leaves, spinach has a shallow root system but offers a much higher nutrient payoff. It handles the fickle British weather brilliantly and can tolerate a bit of afternoon shade.
Why it’s perfect: Freshly picked homegrown spinach tastes leagues better than the slimy bags you get at the supermarket.
Top Tip: Harvest the outer leaves regularly to encourage the plant to keep producing tender new growth from the centre.
Need the perfect container? If you haven’t picked up a patio planter yet, check out our review of the Grand Patio Elevated Raised Garden Bed. It’s the ideal depth for these five crops and saves your back from bending down to water them.
The Secret to Shallow Planter Success
Because shallow planters hold less total compost, they do two things quickly: they dry out fast and they run out of nutrients faster than an open garden plot.Check out My Recommended Organic Liquid Seaweed Feed on Amazon to keep your shallow crops thriving.
To get a massive harvest, make sure you water them daily during dry British summer spells and feed them with an organic liquid seaweed fertiliser once every two weeks once the plants get established.
Want to start your patio garden this weekend?
If you want to get these crops growing right away, here is the exact checklist of what you’ll need to set up:
- The Container: You need a container with decent drainage that fits your space. We highly recommend the rot-resistant Grand Patio Elevated Raised Garden Bed—it is the perfect height and depth for all five of these vegetables.
- The Compost: Don’t use soil from the garden (it gets too compacted in pots). Grab a bag of high-quality peat-free compost, like Levington Peat-Free Multi-Purpose Compost, which has enough nutrients to feed your young plants for the first six weeks.
- The Seeds: To get the quickest, most satisfying results, start with a packet of French Breakfast Radish Seeds and some Mixed Salad Seeds. They sprout in days and will give you a massive confidence boost!