March Growing Guides

March often feels as if it’s still winter, especially with it’s famous ‘March winds’ which can quickly make you wish you were back inside where it’s warm. But in a polytunnel, the wind isn’t a problem and you can focus instead on what’s happening to all your overwintering plants – which are suddenly growing, and many of which are either actively bolting or thinking about it.

Broad beans and peas planted in January should begin to flower this month. However, if you planted them in late autumn they will be developing small pods. These will become a valuable source of food in the ‘hungry gap’, when there’s nothing much left from winter and the spring crops aren’t yet ready, which begins around the end of the month.

Overwintering plants such as celeriac, lettuce and pak choi will be very keen to bolt this month, but you can delay things by trimming off all but a few leaves. This will slow them down enough to allow you to continue to enjoy them well into April.

Celery will have recovered from the winter lull and should now be producing some beautiful edible stems. It won’t last, so make the most of it!

While frost will have invariably killed off all my outside chard, the polytunnel plants will have survived but are now determined to bolt. However, one of the great things about chard is that the flavour of the leaves doesn’t change, and as bolting is a long and quite spectacular process (flowering chard plants well over 2m tall...) they will tide you over until the younger plants are ready to pick from in June. A few plants in the polytunnel guarantees a year-round crop of this, surely one of the most valuable of all the ‘green leaf’ plants – and one that you hardly ever see in the shops.

If you started off any tomato plants under lights in January they should begin flowering about now. As it’s roughly 60 days from seed to flower and another 60 days from flower to fruit, early tomato flowers means a crop that you can be enjoying long before any blight appears.

If you planted elephant garlic in October it should really be getting going now, and may easily be well over a foot tall.

Top Tips

Sometime in March your polytunnel will take over from windowsills and cold frames as the best place for new seedlings, so you need to provide somewhere where they will a) get plenty of light and b) won’t be constantly in the way. Rather than taking up valuable floor space, why not hang some staging from the crop bars? Ideally you want something that light can penetrate so only a little shade is cast on the beds beneath. A simple wood frame made from some scraps of 25mm x 50mm timber and covered with a sheet of rectangular wire mesh (or similar) is ideal. Then, once your plants are big enough to go into a bed, you can take the staging down until it’s needed again. Mine usually goes up in March, comes down in May, and goes back up again in late August for the autumn/winter crops.

As you take out the overwintering plants, fork in some new compost so the beds can sustain the season ahead – unless, of course, you are growing crops that prefer soil that is not too rich, such as carrots. Always keep note of what grew where so you can maintain a good crop rotation. This avoids nutrient deficiencies and also breaks the cycle of pests and diseases which can otherwise turn into a major problem.

March offers us a wide variety of weather. On colder days it’s easy to forget that in the warmer climate of the polytunnel, plants are coming out of dormancy and therefore need more water than at any time over the past several months. Don’t forget ventilation, either, or you could have a lot of sick plants on your hands. Taking care of both these will help ensure everything gets off to a great start, and stays that way.

What To Grow

Aubergine, cabbage, carrot, cauliflower, celeriac, chard, coriander, fennel, garlic/elephant garlic, kohlrabi, lettuce, spring onion, peppers, radish, rocket, spinach, strawberry plants, tomato.

March is actually a bit late for peppers. They do best when started really early, so if I planted them in February I don’t usually sow more in March. However, if you missed February, do it now! You should still get a decent crop.

Everything on both the ‘sowing’ and ‘harvesting’ lists, plus peas, broad beans and potatoes.

Beetroot, sprouting broccoli, cabbage, carrot, cauliflower, celeriac, celery, chard, coriander, kohlrabi, lettuce and other salad greens, spring onion, pak choi, radish, rocket, spinach, turnip.

Please see our Top Of The Crops for a list of over 80 Vegetables, Fruits, Herbs and Spices, Flowers and Exotics.

< Back

January Growing Guides

Swipe to scroll through tabs

About First Tunnels

We’re a close-knit bunch of skilled professionals who take an enormous pride in the quality and versatility of our products, But we’re enthusiasts too - we use our own products, and that means we’ve introduced lots of improvements and innovations over the years…based on first-hand everyday practical experience. We work hand-in hand with top growing experts. We even have our own allotment for some seriously hands-on gardening, often accompanied by communal summer and winter barbecues because all work and no play would be very dull!

Polytunnel Community

Reviewed by you, Followed by you, Liked by you and listened to by us. We have a strong online polytunnel community, 35k Facebook Fans, 10k Twitter Followers and over 3m YouTube Views. Our community of dedicated, passionate Polytunnel gardening friends, love to share their sowing tips, growing hints and harvesting secrets with each other. But more importantly for you, as a customer or a potential customer, you can post your comments in all their glory or gory details. Come and join the Polytunnel family.

Construction Help & Advice

Our six man construction team has a wealth of polytunnel construction knowledge and are more than happy to share tips and advice with any of our customers. Many of the team have been quite literally 'hands on' developing the First Tunnels vast array of construction videos and in depth instruction guides. Our construction team are available to answer your questions and help in whatever way they can. Simply call 01282 601253 on week days between 9am-5pm...PLUS weekend cover on 07801 601253, between 9am-5pm.

Frequently Asked Questions

We are proud of our products and the time that we have put in to making sure that all our products are first class. We understand that purchasing a polytunnel is a considerable investment, and whilst we have lots of help and advice on this site, Facebook, YouTube, Twitter and blog pages many people like to compare and contrast before they commit their hard earned cash to buying. To this end we have compiled a list of the most common questions and provide 10 top reasons why First Tunnels Polytunnels is the top choice.

Getting Growing

Part of the fun of owning a polytunnel is picking the brains of people who really know how to make the most of the real growing potential. So we're making it easy for you...with some of the best brains in the business! This site now includes features, produced exclusively for First Tunnels by Andy McKee and Mark Gatter - best-selling authors of 'How to grow food in your Polytunnel' and 'The Polytunnel Handbook'. We also have videos from BBC’s Gardeners’ Question Time presenter, Paul Peacock. We also have a host of growing guides from Sam Youd, presenter & judge for the Royal Horticultural Society & Tatton Park Head Gardener.

Other Useful Stuff

What better way to learn about company dependability, product quality and customer service than to hear it straight from other consumers? By giving customers the opportunity to share their First Tunnels shopping experience, we believe this is the best reflection of our companies’ product and service. To help reinforce credibility, popularity and reputation, we have subscribed to not one, not two...but THREE independent review companies. We value all feedback, good, bad or ugly and hope to build a long lasting relationship with our customer, through our high quality products and friendly service, to ensure they do not hesitate to order again and again with First Tunnels in the future.