The Perfect Spring Treat: Growing Asparagus Successfully In The UK

Asparagus is my favourite spring treat and I eagerly await the time it’s in season. And there is nothing better than homegrown asparagus.

I always thought that growing asparagus is difficult and not worth it. But after we moved to the country, which gave me more space to grow vegetables, I decided to give it a go.

I’m so glad I did, because it’s not difficult at all. On the contrary, it’s one of the easier veggies to grow. And did you know that asparagus is a very healthy veg? (Guo et al., 2019)

So here is my guide of how to grow asparagus in the UK. But first…

… Asparagus Is A Perennial

Unlike most veggies that you probably grow, asparagus is a perennial. This means you plant it once and it will come back every year providing you with delicious tender spears every spring for up to two decades.

This is great, because it means that growing asparagus is really cheap after the initial investment. And like most perennial veggies, it doesn’t need much care.

Besides, you can harvest when most other vegetables plants haven’t even started to flower. That’s great, because it will give you homegrown food for a longer period.

Now we have cleared that up, let’s get to it…

To Grow From Seed Or Crown, That Is The Question

The first decision you have to make is whether to grow your asparagus from seed or from crown, which is similar to a plug plant when it comes to tomatoes, cucumbers, or courgettes.

There are pros and cons to both, and which one you choose is up to you.

As you can see, growing from seed is cheaper. But it involves more work and you rely on your seeds actually germianting. And crucially, you have to wait for 3 years until you can start to harvest.

If you grow from crown, you only have to wait 2 years and you don’t need to worry about germinating seeds and transplanting the seedlings.

I opted for growing from seed, becauses I prefer it. But I have to admit, I struggled to get my asparagus seeds to germinate and only managed to get one plant. I tried again a year later and didn’t get any of the sown seeds to germinate.

However, I did end up with one plant, which I was very pleased about.

Surprisingly, you can get more varieties if you grow from crown. Normally, it’s the other way round. Here are my favourite varieties you should try:

• Pacific Purple – purple asparagus spears that have a sweet and tender taste. Available as crowns.
• Rafaelo – late-season variety that you only start harvesting in July. Grow with an early variety for a longer harvesting period. Available as crowns.
• Vittorio – a white cultivar, but you have to cover the spears with soil to keep them white. Can also be grown above ground as green spears though. Available as crowns.
• Ariane F1 – a green variety that can be harvested in the first year, albeit only lightly. Available as seeds.

Here you have it, you know all you need to know and you can choose whether to grow from seed or crown.

Growing Asparagus From Seed

If, like me, you want to opt for the path of the seed, your journey will start in February, when you sow the seeds.

Sow one seed per small pot and put on a windowsill or in a propagtor in a greenhouse or polytunnel. The tricky part is to create the right conditions for the seeds to germinate.

They need a soil temperature of between 13°C–20°C, depending on the variety you are growing. Check the seed packet for the right temperature.

I think this it the part I struggled with. I first had the pots on the windowsill in our library, but that didn’t work. I reckon it just was to warm, as this room can get quite warm when it’s sunny, being south facing.

I then moved it to my office, which is north facing and therefore cooler. This did the trick and I managed to germinate one seed.

Keep the compost moist, but not wet. Once they are big enough to handle, transplant into a bigger pot. Keep the seedlings in a warm, bright spot and water them regularly.

Ideally, you wait until June the following year to plant them into their bed. I didn’t do that, because I was far too eager. And it did’t look like it caused any issues.

Keep in mind that your asparagus bed will not be available for annual veg, as it will come back year after year. Especially if you have put more asparagus plants in the bed.

It’s wise to harden off your asparagus plant before planting it out. This will ensure it aclimatises well to the new conditions.

Preparing The Soil

It’s important to prepare the bed well before planting out your asparagus plant. You want well-draining soil, other than that the soil type doesn’t matter much.

Dig in a good amount of organic matter, such as homemade compost, before planting out your asparagus. If you have a no-dig garden, add a 5cm layer of mulch and plant the asparagus straight into the mulch.

You want to choose a bed that ideally has full sun, although asparagus plants will tolerate some shade. Ours gets the sun from late morning onwards and does well. A spot that is sheltered from winds is preferable, as the spears will grow quite tall over summer.

Growing Asparagus From Crown

If you have opted to buy an asparagus crown, congratulations, you can skip all the faff and plant them straight in your asparagus bed, which should be prepared as we have described above.

They will already be a year old when they arrive and should be planted out as soon as possible. However, planting an asparagus crown is different to other plug plants.

First dig a hole that is big enough for the roots to fit in once they are spread out. This can be anywhere around 30cm wide and 20cm deep. So far, so good.

Then make a hill of about 10cm in the middle of the hole. Sit the part of the crown with the asparagus tips on top of the hill.

Finally, carefully spread out the roots, and cover with soil. Don’t press it down though. At the end, you only want the tips above the soil.

Water well and add a layer of mulch, preferably homemade leaf mulch, but any mulch will do. And there you go, your asparagus plant is in.

If you have more than one plant, space them 45cm apart, whether you grow them from seed or grown. This will ensure they have enough space to thrive.

Caring For Your Asparagus Plants

While your new asparagus plants settle in, make sure you water them regularly over their first summer.

After that, they don’t need much care. Water every now and then, but don’t worry too much, as they are drought tolerant. (Zhang et al., 2024) However, during long dry periods, they will need to be watered.

Once the harvesting period has finished, support each spear with a cane to keep it from falling over. Asparagus spears grow surprisingly tall.

Make sure you keep your asparagus bed as weed-free as possible.

In autumn the leaves will start to turn yellow. At this point, cut each spear at ground level. In winter, add a thick layer of mulch to the bed. This will stop weeds and feed the asparagus in spring.

It’s not necessary to feed asparagus plants if you add mulch every year, which makes them very easy to grow. And that’s it, simple, eh?

Harvesting Asparagus Plants

Growing asparagus needs patience. If you grow from seed, you have to wait until the fourth year before you can start harvesting. With crowns it’s the thrid year. This is necessary to ensure the plants are well established and will produce a good yield.

Once you have reached this point, harvesting will start here in the UK around mid-April. It’s the most exciting thing to spot the first spears poking through when your other seedlings are still in their pots on a windowsill or greenhouse/polytunnel.

Cut them with a sharp knife or scissors when they are about 20cm (8in) long. You want to cut them 2.5cm (1in) below the soil.

In the first harvest year, harvest for about 6 weeks, so from mid-April to mid-June. After that, you can harvest until end of June.

Once it get’s warmer, they grow incredible fast, so you might have to harvest every 2 – 3 days. Keep harvesting so that the plant continues to produce spears.

From one plant you can expect about 10-15 spears during the harvesting period. Having more than one plants means you can have a good amount of spears each spring.

You tend to get one, maybe two spears at a time, so to get enough for a meal will take a week or so. You can put the harvested spears in a glass of water in the fridge. This will keep them fresh for up to two weeks.

Pests And Diseases

The good news is that asparagus plants are very hardy and aren’t affected much by pests or diseases. The asparagus beetle can cause problems though.

These little bugs emerge in May, and will eat the leafes and nibble at the stems of asparagus plants. They can cause the spears to turn yellow, because they remove the bark, cuasing the stem to dry out.

Like with any pests try to tolerate them whenever possible, as they are part of the ecosystem. Small numbers are unlikely to cause an issue, only an ifestation can cause a reduced yield.

We don’t encourage the use of pesticides, as they aren’t good for our environment. Here is how to keep this pest under control without chemicals:

• Encourge beneficial insects and animals to your garden: wasps, ground beetles, birds and frogs all eat this beetle and its larvae
• Make sure you cut off and dispose of the stems at the end of the year: the asparagus beetle might overwinter in them
• Check and pick off any beetles or larvae you spot: this can keep numbers down
• Use companion planting: it’s said that tomatoes will repel the asparagus beetle when grown with asparagus

The only disease that could befall your asparagus plant is violet crown rot. If this happens, you have to dig out your plants and start anew. Ideally in a different bed, as this soil-borne disease will stay in the soil.

To minimise the risk of this disease striking in your asparagus bed, take these measures:

• Ensure you have well-drained soil – dig in a lot of organic matter if you have heavy soil or create raised beds for your asparagus plants
• Plant asparagus plants well spaced out – giving at least 45cm room between plants will ensure good air circulation
• Remove any affected plant immediately – this might help the disease from spreading to other plants in the bed
• Keep the bed free of weeds – weeding regularly will ensure the risk of any disease is minimised

Here you go, now you know how to grow asparagus in the UK. Why not give it a go this year? Happy Growing!