Your Complete Guide on How to Grow Mustard Greens

Do you know how to grow mustard greens? What makes mustard greens particularly brilliant for British growers is their versatility. Whether you’re working with a small patio container in Manchester or a proper vegetable patch in rural Somerset, these hardy plants will reward your efforts. I’ve grown them successfully in both settings, and I’ve found they’re remarkably forgiving of the typical mistakes new gardeners make. They don’t demand constant attention, they cope well with our grey skies, and unlike many salad crops, they actually prefer cooler temperatures. In my experience, they’re the perfect crop for anyone looking to extend their growing season beyond the summer months.

How to Grow Mustard Greens

Before you start learning how to grow mustard greens, it’s worth gathering everything you’ll need. I’ve found that having everything to hand makes the process much smoother, particularly if you’re new to growing your own veg. For more on this, see our guide on from seed to stunning white heads: growing cauliflower.

Seeds and Growing Medium

You’ll need mustard green seeds, which come in several varieties. I’d recommend starting with a straightforward variety like ‘Red Giant’ or ‘Green in the Snow’ for your first attempt. These are reliable performers in British conditions and widely available from garden centres and online seed suppliers. You’ll also need a good quality multi-purpose compost or, if you’re sowing directly outdoors, well-prepared garden soil. I prefer peat-free compost, which has improved considerably in recent years and works just as well as the traditional stuff.

For container growing, which I do extensively on my balcony, you’ll want pots at least 20cm deep with drainage holes. Mustard greens don’t need enormous containers, but they do need decent depth for their roots. If you’re growing in the ground, you’ll need a fork or spade for soil preparation.

Basic Equipment and Materials

A watering can with a rose attachment is essential for gentle watering, particularly when seeds are germinating. I’ve killed more seedlings with overly enthusiastic watering than I care to admit, so a fine rose really does make a difference. You’ll also want some plant labels, because different varieties look similar when young and it’s easy to forget what you’ve planted where. You might also find from seed to harvest: growing chinese cabbage successfully helpful.

For protection against pests, which we’ll discuss later, horticultural fleece or fine mesh netting is incredibly useful. Flea beetles are particularly fond of mustard greens, and I’ve learned the hard way that prevention is better than cure. A hand trowel and some organic fertiliser complete the basic kit. I use blood, fish and bone or a balanced organic feed, though mustard greens aren’t particularly hungry plants.

Step-by-Step Instructions

Right, let’s get into the actual process of how to grow mustard greens from start to finish. I’ll walk you through each stage, including the bits that caught me out when I first started.

Step 1: Choosing Your Timing and Location

Timing is genuinely important with mustard greens. Unlike tomatoes or courgettes that need warm summer weather, mustard greens actually perform best in cooler conditions. I sow mine in early spring (March to April) for a late spring harvest, or in late summer (August to September) for an autumn and winter crop. The autumn sowing has become my favourite because the plants grow steadily through cooler weather and don’t bolt to seed like they might in summer heat.

Location-wise, mustard greens prefer a spot with partial shade, particularly if you’re growing them in warmer months. I’ve had excellent results in areas that get morning sun but afternoon shade. They’ll tolerate full sun in spring and autumn, but during any warm spells, partial shade prevents them becoming too peppery and tough. The soil should be reasonably fertile and well-draining. I’ve grown them successfully in heavy clay soil (common across much of the Midlands and South), but I always work in some compost first to improve drainage.

Step 2: Soil Preparation and Sowing

Prepare your soil by removing weeds and working it over with a fork. Mustard greens prefer a pH between 6.0 and 7.5, which is fairly standard for vegetable growing and shouldn’t require any special amendments for most British gardens. I add a layer of compost and a handful of organic fertiliser, then rake the surface level.

For direct sowing outdoors, create shallow drills about 1cm deep and 20-30cm apart. Sow seeds thinly along each drill, then cover lightly with soil and water gently. The key word here is ‘thinly’. I used to sow far too thickly and waste seeds that I’d then have to thin out. Now I space seeds about 2-3cm apart from the start, which saves work later.

If you’re starting seeds indoors or in a greenhouse, fill small pots or module trays with compost, sow one or two seeds per module about 1cm deep, and keep them somewhere bright and cool. A windowsill works fine, though avoid anywhere too warm. Mustard greens germinate quickly, usually within 5-7 days, and you’ll see seedlings popping up remarkably fast.

Step 3: Thinning and Transplanting

Once your seedlings have developed their first true leaves (the second set of leaves that appear, which look different from the initial seed leaves), it’s time to thin them. This is probably my least favourite job in the garden because it feels wasteful, but it’s necessary. Thin direct-sown seedlings to about 15-20cm apart for leaf varieties, or 30cm apart if you’re growing larger heading types.

The thinnings don’t have to go to waste, though. I use them as microgreens in salads – they’re perfectly edible and have a lovely mild peppery flavour. For seedlings started indoors, transplant them once they’re about 5-7cm tall and have a decent root system. I usually wait until they’ve been hardened off (gradually acclimatised to outdoor conditions) over a week or so, then plant them out at the same spacing as direct-sown crops.

Step 4: Ongoing Care and Maintenance

Mustard greens are fairly low-maintenance, but they do need consistent care for the best results. Water regularly, particularly during dry spells. I aim to keep the soil consistently moist but not waterlogged. In my experience, irregular watering leads to poor leaf quality and can trigger bolting. During typical British weather, natural rainfall often does most of the work, but I water deeply once or twice a week during dry periods.

Weeding is important early on because young mustard greens don’t compete well with weeds. Once the plants are established and their leaves meet between rows, they suppress most weeds naturally. I don’t usually feed mustard greens heavily, but if growth seems slow, a liquid feed every couple of weeks helps. Too much nitrogen can make the leaves excessively strong-flavoured, so I go easy on high-nitrogen fertilisers.

Step 5: Harvesting Your Crop

This is where growing mustard greens gets really satisfying. You can start harvesting baby leaves as soon as they’re large enough to use, usually 3-4 weeks after sowing. I use the cut-and-come-again method, snipping outer leaves and leaving the centre of the plant to continue growing. This extends the harvest period considerably.

For full-sized leaves, wait until they’re about 15-20cm long, which typically takes 5-6 weeks from sowing. I harvest in the morning after any dew has dried but before the day warms up, as this is when leaves are crispest. Use a sharp knife or scissors to cut leaves cleanly. If you’re growing heading types, harvest the entire plant once the head feels firm. I’ve found that mustard greens become increasingly peppery as they age, so don’t leave them too long if you prefer a milder flavour.

Common Mistakes to Avoid

I’ve made plenty of mistakes growing mustard greens over the seasons, and I reckon sharing them might save you some frustration. These are the issues I see most often when helping other gardeners troubleshoot their crops.

Growing in Overly Warm Conditions

The biggest mistake I see is treating mustard greens like they’re a summer crop. They’re not. When temperatures consistently exceed about 25°C, mustard greens bolt (run to seed) rapidly. The leaves become unpleasantly hot and bitter, and the plant’s energy goes into flowering rather than producing the tender leaves we’re after. I learned this the hard way during a particularly warm May when my entire crop bolted within a week.

The solution is simple: time your sowings for cooler periods, provide shade during warm spells, and keep plants well-watered. If you’re growing in summer, choose a shadier spot or use shade netting. Honestly, though, I’ve found it’s easier to simply avoid mid-summer growing and focus on spring and autumn crops instead.

Inadequate Pest Protection

Flea beetles are absolutely the bane of brassica growers, and mustard greens are particularly attractive to these tiny jumping insects. They create characteristic small holes in leaves, and in severe infestations, they can destroy young plants entirely. I lost my first two sowings to flea beetles before I worked out what was happening.

The answer is covering plants with fleece or fine mesh netting immediately after sowing or planting out. The beetles can’t reach the plants if they’re properly covered, and the material doesn’t interfere with growth. I keep my mustard greens covered until they’re well-established and growing vigorously. Larger plants can tolerate some beetle damage, though it’s never ideal. Keeping soil moist also helps, as flea beetles prefer dry conditions.

Inconsistent Watering and Poor Soil

Mustard greens are quick-growing, and that rapid growth requires consistent moisture. I’ve noticed that plants subjected to dry spells followed by heavy watering develop tough, bitter leaves and are more prone to bolting. The goal is steady, even moisture throughout the growing period.

Poor soil is less of a deal-breaker than with some crops, but mustard greens definitely perform better in reasonably fertile ground. In my allotment’s poorer soil, the plants grow more slowly and produce smaller leaves. Adding compost before planting makes a noticeable difference to both growth rate and leaf quality.

Expert Tips

After growing mustard greens in various conditions and locations, I’ve picked up a few techniques that really improve results. These aren’t essential, but they’ll help you get more from your plants.

Succession Sowing for Continuous Harvest

Rather than sowing a large batch all at once, I sow small amounts every two to three weeks throughout the growing season. This provides a continuous supply of tender young leaves rather than a glut followed by nothing. I typically sow a row or half a module tray every fortnight from March through to September, skipping July when it’s usually too warm.

This approach suits how I actually use mustard greens in the kitchen. I want a handful for salads or stir-fries several times a week, not a wheelbarrow full all at once. It also spreads the workload and reduces waste. In my small urban garden, succession sowing makes much more sense than trying to store or preserve large harvests.

Variety Selection for Different Seasons

Not all mustard green varieties perform equally across seasons. I’ve found that varieties like ‘Red Giant’ and ‘Red Frills’ are excellent for autumn and winter growing because they’re particularly cold-hardy. They’ve survived temperatures down to about -5°C in my garden without protection, though growth slows considerably in deep winter.

For spring sowing, faster-growing varieties like ‘Green in the Snow’ or ‘Mizuna’ (technically a related crop but grown the same way) work brilliantly. They mature quickly before warm weather arrives and bolting becomes an issue. I also grow different varieties simultaneously to provide varied flavours and textures. Some are mild enough for children, while others pack a proper mustard punch that adults appreciate.

Using Containers for Flexibility

I’ve become a real advocate for container growing with mustard greens, even though I now have allotment space available. Containers offer flexibility that in-ground growing doesn’t. You can move pots into shade during warm spells, bring them closer to the kitchen for easy harvesting, and extend the season by moving containers into a greenhouse or cold frame when temperatures drop.

I use containers at least 20cm deep and wide, filled with good quality compost. The plants don’t need huge pots, which makes this approach practical even on small balconies or patios. Container-grown mustard greens do need more frequent watering than those in the ground, particularly during dry weather, but that’s the only real disadvantage. I’ve grown excellent crops in containers throughout cities like Leeds, Birmingham and Edinburgh, proving they adapt well to urban conditions.

Extending the Season with Protection

With minimal protection, you can harvest mustard greens almost year-round in milder parts of Britain. I use cloches or a cold frame to extend both ends of the season. Spring sowings under cloches can start several weeks earlier than unprotected outdoor sowings, while autumn crops continue producing well into winter with protection.

Even a simple layer of horticultural fleece makes a significant difference. I’ve harvested fresh leaves in January from autumn-sown plants under fleece in my Surrey garden, which isn’t particularly mild. Growth is slow during the coldest months, but the plants survive and the leaves remain usable. This winter harvesting capacity is one of the features that makes mustard greens so valuable for year-round salad growing.

Frequently Asked Questions

How long do mustard greens take to grow from seed?

Mustard greens are pleasantly quick, which is part of their appeal. You can start harvesting baby leaves as cut-and-come-again salad within three to four weeks of sowing, though I usually wait until they’re slightly larger for better flavour. For full-sized leaves, expect five to six weeks from sowing to harvest under good growing conditions. Autumn and winter crops grow more slowly due to lower temperatures and shorter days, potentially taking eight to ten weeks to reach full size, but they’re still faster than most brassicas. The rapid growth makes them brilliant for impatient gardeners or anyone wanting quick results from a new vegetable patch.

Can I grow mustard greens indoors on a windowsill?

Yes, though with some limitations. I’ve grown baby mustard greens successfully on bright windowsills for cut-and-come-again harvesting. They won’t develop into full-sized plants indoors unless you have exceptional light, but for microgreens and baby salad leaves, windowsills work fine. Choose a south-facing window for best results, and be aware that indoor conditions are usually too warm for optimal growth. The leaves may be more peppery than outdoor-grown plants, and you’ll need to water more frequently as pots dry out faster indoors. Sow thickly in shallow trays, harvest when leaves are 5-7cm tall, then resow for continuous production. It’s not a substitute for proper outdoor growing, but it’s useful during winter or if you lack outdoor space.

Why are my mustard greens so peppery and tough?

This is almost always a temperature and watering issue. Mustard greens become increasingly hot-flavoured and develop tough leaves when grown in warm conditions with inadequate water. The plant’s natural response to stress is producing defensive compounds, which manifest as that intense peppery bite. If your plants are in full sun during warm weather, they’ll be much stronger-flavoured than those grown in cooler, shadier conditions. Inconsistent watering exacerbates the problem. To produce mild, tender leaves, grow mustard greens during cooler months, provide afternoon shade if necessary, and maintain consistent soil moisture. Harvesting leaves when young, before they become tough, also helps. Some varieties are naturally milder than others, so variety selection matters too.

Do mustard greens need any special soil conditions?

Mustard greens are fairly adaptable and will grow in most reasonable garden soils, which is part of why I recommend them for beginners. They prefer a pH between 6.0 and 7.5, which covers most British gardens without amendment. Soil should be reasonably fertile and well-draining, though they’re not particularly fussy. I’ve grown them successfully in heavy clay (common across much of England) provided I’ve worked in some compost first to improve drainage. They don’t need the rich, heavily-manured soil that hungry feeders like courgettes demand. A moderate application of compost or well-rotted manure before planting provides sufficient nutrients for the entire growing period. Avoid very poor, dry soil or waterlogged conditions, but otherwise, standard vegetable garden soil works perfectly well.

Can mustard greens survive winter outdoors?

Yes, many varieties are remarkably cold-hardy, though survival depends on your location and the severity of winter conditions. In milder southern and coastal areas, autumn-sown mustard greens often survive unprotected through average winters, providing occasional harvests during milder spells. In colder regions or during harsh winters, they’ll need protection from fleece, cloches or a cold frame. I’ve had varieties like ‘Red Giant’ and ‘Green in the Snow’ survive temperatures down to about minus 5°C without protection, though growth stops during very cold periods. The plants essentially go dormant, then resume growing when temperatures rise. For reliable winter harvesting, I’d recommend providing at least basic protection. Even a simple cloche makes the difference between plants that merely survive and those that continue producing usable leaves through winter.

What’s the difference between mustard greens and mustard seeds?

This confuses people regularly, and it’s a fair question. Mustard greens are the leafy vegetables we’ve been discussing, harvested young for salads and cooking. Mustard seeds, used for making the condiment, come from the same plants but they’re left to flower and set seed rather than being harvested for leaves. The plants are botanically related but grown very differently. If you want salad leaves, you’ll harvest long before flowering occurs. If you wanted mustard seeds (which is much less common in home gardens), you’d need to let plants bolt, flower and develop seed pods, then harvest and dry those seeds. Most gardeners growing mustard greens consider flowering a failure because it signals the end of leaf production, whereas seed growers actively want flowering to occur.

Final Thoughts on How to Grow Mustard Greens

Learning how to grow mustard greens has genuinely changed my approach to salad growing. They’re so much more reliable than lettuce in our changeable British climate, and that peppery flavour adds real character to meals. I particularly value their willingness to grow during the cooler months when fresh salad options become limited and expensive.

What I appreciate most is their forgiving nature. They’ll tolerate the occasional neglect that’s inevitable in busy lives, they cope with our grey skies better than many crops, and they don’t demand constant feeding or complicated care routines. Whether you’re a complete beginner working with a few containers on a balcony or an experienced grower with a proper vegetable patch, mustard greens offer reliable results without excessive fuss.

Start with a small sowing this spring or autumn, follow the straightforward steps I’ve outlined, and you’ll likely be pleasantly surprised by how easy and rewarding these plants are to grow. Once you’ve tasted freshly picked mustard greens from your own garden, shop-bought salad bags never quite measure up. Give them a try, and I’d be surprised if they don’t become a regular fixture in your growing rotation.

Author: Megan Walker

Megan focuses on seasonal food, kitchen garden growing, and how households can reconnect with where their food comes from. Her writing blends practical growing advice with ideas for cooking and eating in season. With a passion for fresh ingredients and sustainable living, Megan’s articles help readers make the most of local produce while supporting British farms.