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How to grow radish indoors

how to grow radishes indoors

Salad crops are generally a great choice for indoor growing. They don’t need too much space, are often quick to mature and are mostly easy to pick and prepare.

If you’d like to try growing veggies at home and want to start simple, radishes are one of the quickest and easiest crops to grow indoors.

They mature super fast, from tiny seed to ready to eat in about 30 days. You can be crunching on delicious home-grown radishes while other vegetables are still getting their growing boots on!

Plus there are quite a few varieties to try, with different shapes, sizes, colours and subtly different flavours to keep things interesting.

Radishes make an excellent choice for an indoor veg garden. So, if you want to give them a go, here’s how you grow radishes indoors.

Growing radishes indoors – the basics

Best radish varieties for indoor growing

For the purposes of indoor growing, where space is limited, you’ll get the best yield from smaller, faster maturing radishes. Here are just a few that are great to grow indoors:  

Cherry Belle

The quintessential red round radish. One of the quickest varieties to mature (about 3 weeks) and as lovely to look at as to eat. Cherry Belle only grows to about an inch across, making it ideal for smaller and/or shallower containers.

French breakfast radish
French Breakfast radish

French Breakfast

An elegant scarlet cylindrical variety with a white tip, reaching around 2 inches long and an inch wide. Mild in flavour and perfect for dipping in salt. Matures in around 4 weeks.

Scarlet Globe

Another classic round radish with bright red skin, crisp white flesh and a mild peppery flavour. Best eaten at about an inch in diameter, which takes roughly 3-4 weeks.

Zlata

A Polish native, plum shaped and golden yellow with bright white flesh. Crunchy and slightly spicy, usually ready to harvest at 3 weeks when less than an inch wide.

Always direct sow your radishes

In common with carrots, parsnips and other root crops, radishes don’t like their roots disturbed once they’re up and running. 

The seedlings don’t take well to being transplanted, so there’s no need to start them off in seed trays and pot them on once they’ve sprouted. 

Radishes are happiest if you sow them directly in a container and leave them there to grow. Nice and easy – plus you save money on seed trays and seed compost. Win-win. 

Try growing with other edible plants

As they’re ready to eat so quickly, radishes are ideal for sowing between rows of lettuce as a catch crop or intercrop. This means you can harvest and enjoy them while you’re waiting for your lettuces to mature.

It needn’t only be lettuce – you can fit them around other slower growing vegetables or herbs you have growing indoors and they will usually grow quite happily.

They don’t need much space at all, nor to be sown in neat rows. Any spare few centimetres in a container or pot can be used to sow a scattering of radish seed. 

Where to grow radish indoors

As a root crop, radishes are fairly tolerant of shade. They’ll usually grow well indoors even if your home isn’t flooded with natural light.  

Unlike some indoor grown vegetables, you won’t need to worry about supplementing radishes with electric grow lights. 

They don’t need anywhere near as much sunlight as fruiting crops, like tomatoes, peppers and cucumbers, for example.

As long as you have a window where they can receive a good 5-6 hours of daylight, your radishes will be perfectly happy on a windowsill. 

And since they don’t need direct sun, the window doesn’t even have to be south facing. You should be able to grow radishes in a west, east or even a dull north facing window without any problems. 

How to grow radishes indoors – step by step

What you need:

  • Radish seeds
  • Container with drainage holes (trough shaped is ideal but a large pot will do)
  • General purpose peat-free compost
  • A watering can with a fine rose
  • Misting spray (optional)

1. Sow your radish seeds

You should be able to grow radishes indoors from early spring through to winter, so start sowing in spring. Pick a container at least 6 inches deep to give roots plenty of space.

Fill it to about 2 inches from the top with compost. If you can, choose a rich mix with a loose, open structure so it drains well.

Radishes aren’t especially hungry, so a rich compost should provide enough goodness for your crop. But if you want to add an extra nutrient boost, you can mix in fertiliser before sowing. 

Choose one that’s higher in phosphorus, rather than nitrogen. Too much nitrogen will encourage more leafy top growth rather than swelling the radish root.

Sprinkle the seeds thinly over the compost’s surface, covering them lightly (around 1/4 inch deep) with compost. Firm them down gently with your hands. The aim is to get all your seeds in good contact with the compost.

Give them a water – you’ll want to use a very fine spray for newly sown seeds. I like to use a spray misting bottle which is great for gentle watering.

You could water from the bottom instead, standing the container in a couple of inches of water in the sink. Leave it to soak up water until the top of the compost feels moist.

You might also like: Growing leeks indoors for a healthy harvest.

2. Keep them cool and moist

Keep the compost well watered so it stays not soaking wet but evenly moist. It’s important you never let it dry out completely, especially when seedlings are first emerging.   

Resist the temptation to turn up the thermostat to get your radishes growing more quickly. Radishes are a cool season crop, not a heat-loving one, and will do best between 55 and 65 degrees F (50-55 degrees at night).

Be mindful of the intense heat on hotter days, especially if you’re growing your radishes in a window with direct sunlight.

You may need to water more often and move the container somewhere cooler in the hottest part of the day. 

3. Thin out your seedlings

Your radish seedlings should appear after about a week. Once they have two pairs of leaves, thin them out to leave around 3 inches (7.5cm) between them. 

But don’t waste the discarded seedlings! Those little cuties are radish microgreens and delicious in their own right.

You can chop them into salads or sandwiches to add some peppery punch and crunch (and plenty of goodness).

3. Practise successional sowing for a continual crop

To enjoy a sustained crop of radishes, if you have the space, sow more seeds every couple of weeks to give you a steady supply. This is known as successional sowing, and is very satisfying to master.

If your growing space is limited, you can do it by re-using empty spaces – whenever you pick a radish to eat, sow a seed in its place.

As long as you don’t eat them too quickly, you should always have fresh crunchy radishes to hand.

4. Harvest and prepare your radishes

Don’t wait too long to pick and enjoy your radishes. It’s better to harvest them a little younger and smaller than leave it too late. 

Older radishes can turn spongy and dry, or tough and woody. They also tend to get hotter and less sweet with age. 

For smaller varieties, pick them when they’re about an inch wide. You can easily lift them up for a peek to see how they’re doing and if they’re too small, push them back in. 

After picking, always give them a good rinse before eating. While radishes are usually eaten raw to give salads colour and crunch, the versatile veggies can also be cooked. 

You can bake them like potatoes, or slice them up and fry them (great for stir fries). They also take surprisingly well to boiling. Boil them whole for 10 minutes and drizzle them with butter and a pinch of sea salt. Yum.  

And don’t throw out those leafy radish tops – they make lovely peppery salad greens. Or if you’re feeling adventurous, you can make them into a delicious radish greens pesto

Radish growing problems

Though they’re an easy crop, there are a few problems you might run into when growing radishes indoors – but forewarned is forearmed! Here are a few issues you could encounter, and their causes, so you know how to prevent them:

Seedlings falling over

Wilting seedlings are likely down to too much heat and/or too little water. Act quickly and they might be salvageable. Give them a thorough water and make sure to keep them moist thereafter. If necessary, move them out of direct sunlight.

Radishes are too small

Your radishes are probably crowded and competing for nutrients. If they’ve been densely sown and haven’t been thinned out enough, it can limit their growth.  

Sacrificing a few seedlings is worth it to ensure a crop of bigger, juicier radishes. And remember, you can eat them so they don’t go to waste!

Radishes are flowering

In hotter temperatures, especially if not well watered, radishes will ‘bolt’ and go to seed. You can remove the flowers and your radishes will still be edible, but bolted radishes are tougher, woodier and more bitter. Sow some more seed – a new crop won’t take long to mature.

Lush green tops but radishes are long and thin/not swelling

This points to too much nitrogen and not enough phosphorus. Apply some high-phosphorus fertilizer before your next sowing and they should bulb up. 

Radishes have split

Splitting radishes are either not receiving enough water, or are being watered too sporadically. Keep compost constantly, evenly moist and avoid extremes of drought and wet.

It’s quick, simple and inexpensive to grow radishes indoors. Along with salad leaves, they’re a great starter crop if you want to get growing delicious organic food at home. Give them a try and see what you think – it’s bound to give you the bug and make you want to grow more!

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