When to plant beetroot seedlings outside – and one clever way to tell if the soil is warm enough

If you sowed your beetroot seeds indoors this year like I did, you’re probably wondering when to plant beetroot seedlings outside.

Learning how to grow beetroot is pretty easy – I even included it in my roundup of the best vegetables to sow in March for beginners, because it was one of my most successful crops when I first started gardening.

If you sowed the seeds indoors to get a headstart this year, it’ll soon be time to plant them outside – but there are a few steps you’ll need to consider beforehand, and one clever tell-tale sign that it's warm enough to bring them outdoors.

Gardeners tend to use a general timeframe to figure out when to plant beetroot seedlings outside.

‘You can usually plant beetroot seedlings outside around four to six weeks after sowing indoors,’ says Rachel Cole, seed manager at Mr Fothergill’s. ‘This can be done from late March to May, depending on your local climate and when you started sowing.’

There’s actually a really clever way to tell if your garden is ready for your beetroot seedlings, according to Thompson & Morgan’s horticultural expert Annelise Brilli.

‘Once weed seedlings start to rapidly germinate on prepared soil, you’ll know that soil temperatures are warm enough to plant your beetroot seedlings,’ she says. ‘Depending on where you are in the country and the season, this should be around late March or April.’

Don’t plant them out all at once, though – especially if you decide to move your seedlings outdoors earlier in the season.

‘Whether you've raised seedlings indoors or picked up plug plants from the garden centre, it's important to acclimatise them before life outdoors,’ explains Rachel from Mr Fothergill’s. ‘This process, known as 'hardening off', helps young plants adapt gradually to outdoor temperatures and conditions.’

Start by moving your beetroot seedlings outdoors for a few hours each day before increasing the time and moving them into their final growing position. You could even keep a cloche like this bell cloche from Amazon (or a DIY cloche alternative) handy in case temperatures drop.

Where to buy beetroot seeds

If you haven't sown your beetroot yet, there's still plenty of time to get started. You can even sow the seeds outdoors from this month! Here are some of the best places to buy them.

• Mr Fothergill's: I'm growing Beetroot 'Crosbys Egyptian' at the moment. It's one of my favourite beetroot varieties.
• Thompson & Morgan: Beetroot 'Chioggia' is another solid choice.
• Amazon: Shop a huge range of beetroot seeds.

FAQs

Can beetroot seedlings withstand frost?

It all depends on how old your plants are, but seedlings are likely to be a little more tender.

'Mature beetroot plants are fairly hardy and can cope with colder weather, but young seedlings are much more delicate,' explains Rachel from Mr Fothergill's.

Luckily, there are plenty of outdoor plant covers for winter and spring that you can choose from. 'It's best to protect them from frost until they're well-established – especially in early spring,' says Rachel. 'Use a cloche, fleece, or a cold frame to keep them cosy if a late frost is forecast.'

What should you not plant next to beetroot?

While a few companion planting ideas can go a long way to ensure a successful harvest, there are some pairings that you should avoid.

'Avoid planting beetroot next to tomatoes or peppers,' warns Rachel. 'These plants often attract similar pests, which can double the trouble for your crops. They also have different watering and feeding needs, so keeping them apart helps prevent conflicting care routines.'

So, it'll soon be time to plant out your beetroot seedlings. What other vegetables are you planting in April?