What to do in March

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March is an exciting month in the container garden, winter is nearly over. As the days warm and lengthen, it’s time to get your compost and containers ready to go. There is also lots you can sow this month. Having said that, for most crops there is no urgency, you still have plenty of time – and many seeds are much easier to start in April or May than they are in March!

An optimistic month, but we still need be vigilant:  heavy frosts may return at any time.

The advice here is for container gardeners in the Northern hemisphere. The timings will be good for most of the UK. For those of you in cooler or warmer regions, the timings will be similar but slightly different: I recommend you look for a seed sowing calendar for your area and use it in conjunction with the advice here. Container growers in India can check out Monica Bathija’s tips from her roof terrace in Mumbai.

This month

    1. Get your containers and compost ready
    2. Slug vigil
    3. Crops to sow outside
    4. Crops to sow inside
    5. Protect your seedlings
    6. What you can harvest now
    7. Common questions
    • Do I have to start sowing seeds this month? (Quick answer, NO!)
    • What potato varieties are best for containers?
    • What is ‘hardening off’ and why is it important?
One of the first signs of spring. Chive shoots return again at about this time every year.

One of the first signs of spring. Chive shoots return again at about this time every year.

 

1. Get your containers and compost ready.

Next month you’ll be able to move a lot of your crops outside into their final containers. Now is a good time to start organizing your containers and compost in preparation.

You can reuse old compost to grow most of your crops – you’ll just want to add some fertiliser or  worm compost, as all the nutrients will have been exhausted by last years crop.

Although most crops can grow well in rejuvenated old compost, it is much easier to grow tomatoes, aubergines and chillies successfully in new compost. If a good tomato crop is important for you, buy a few bags of new compost now in preparation.

2. Slug vigil

Slugs are most damaging when your plants are small, easily decimating a seedling in one night. There’s few things more dispiriting than waking up in the morning to find all your seedlings have gone (its happened to me, I know!).

By being rigorous about the slug problem now, you will help keep your seedlings safe – and help get the slug population under control for the rest of the season. (Although this is not a magic cure – you’ll still need to be vigilant and keep on top of the problem regularly).

Out of the dozens of different ways to deter slugs, the ‘dusk slug patrol’ is the most effective in a small space. Armed with a torch, you simply pick them off while they’re on the way to their supper.

3. Sow outside

You can sow the following outside – as most will survive light frosts (they are ‘hardy’ in gardening lingo). Starting some crops off outside now can be a good plan, particularly if you don’t have much space inside to raise seedlings. You just need to be aware that if we have a late cold snap, it may ‘check’ (ie slow) the growth of seedlings. When their growth is checked, some seedlings recover and some don’t – in which case you’ll have to sow them again (this happened to my chard, carrots and spring onions last year – they never really recovered, just sat their looking a bit small and feeble!). 

Alternatively, you can sow these crops (except potatoes and artichokes) inside and move them outside on warmer days. This can be a good strategy if slugs or other pests are a big problem or if its very cold. 

If you’re planning to sow carrots, beetroot, or turnips you’ll want to know that they don’t like to have their roots disturbed. Sow them in their final container outside or in modules inside – so that you can move them without disturbing their roots. 

  • Salads (Asian leaves, rocket, sorrel, spring onions).
  • Peas and broadbeans
  • Swiss chard and leaf beat (bright lights or rainbow chard will add vibrant colour and cheer to your container garden).
  • Carrots
  • Beetroot
  • Turnip
  • Potatoes, towards the end of March. Cover them with a cloche or some horticultural fleece, as the growing tips are sensitive to frost.
  • Jerusalem artichokes
Peas can be sown outside now - or started inside and moved outside on warmer days after germination.

Peas can be sown outside now – or started inside and moved outside on warmer days after germination.

4. Sow inside

You can sow the following inside, and move outside once the weather gets warmer (over 10 degrees C) outside. Mid March is the prime time to sow tomatoes, but you can keep sowing them until mid to late April. Peppers, chillies and aubergines need a longer growing season and should be sown as soon possible, and before the end of March if you can.

      • Tomatoes and tomatilloes
      • Peppers and Chillies
      • Aubergines
March is a good month to get tomato seedlings started. They don't like the cold so a bright windowsill inside is the perfect place.

March is a good month to get tomato seedlings started. They don’t like the cold so a bright windowsill inside is perfect if you have one.

5. Protect your seedlings

If you’ve sown some of your seeds outside, you’ll want to protect them if a cold snap is predicted. Although some seedlings will survive frost without protection, they will usually grow faster and stronger with it.

You can protect your crops with cloches (eg upturned water cooler bottles or hoops covered in plastic) . Or you can buy, at  low cost, ‘horticultural fleece’, which you just lie over your crops.

6. What you can harvest now

If you sowed winter salads in August / September last year, you will notice that they begin to grow faster again as the day lengths get longer and the temperature warms. The leaves always seem particularly tasty at this time of year – and they make a very welcome change from root veg!

As growth of salads speeds up again, you can pick more to eat. This salad contains tatsoi, rocket, serifon, pea shoots and ful medame shoots.

As growth of salads speeds up again, you can pick more to eat. This salad contains tatsoi, rocket, serifon, pea shoots and ful medame shoots.

 

7. Common questions

Do I have to start sowing seeds now?

No. You can happily wait until April or May. Seeds will be more willing to grow then and you’ll still have time to start most things off. It’s a lot easier to grow from seed later in the year so if you’re new to growing you may want to try this… or at least don’t be hard on yourself if your early sowings don’t all work out.

The exception is tomatoes, chillies and aubergines, these do need sowing now – but you can always buy these as small plants in April or May instead (also a good a strategy if you don’t have a light space to raise seedling inside).

What variety of potato does best in containers?

Potatoes are categorised by how quickly they grow and mature. ‘First earlies’ are the fastest to grow (ready by June if planted in March), ‘main crop’ grow bigger, and produce higher yields later in the year. For containers, First or Second Earlies are a good choice: they take up less space than main crop varieties, give you the delicacy of new potatoes earlier in the year, and, because you can harvest them in June, free up big pots to grow other crops in (like courgettes or runner beans) over the productive summer months. You can sow them outside from mid to late March.

What is hardening off and why is it important?

This is the term for acclimatising plants that are started inside to the colder temperatures and more turbulent winds outside. This needs to be done gradually – otherwise they may die or be severely set back by the shock.

Plants that are sensitive to frost need to be kept inside at night and on cold days, but, with care, can be put outside – ideally under a cover of some sort – for a breath of fresh air on warmer days. Slowly increase the amount of time they are put outside over two or three weeks, moving them permanently once all risk of frost is over.

Even hardy plants (those not sensitive to frost) that are sown inside need to be hardened off gradually – although they can be planted out before the risk of frost is over.

Moving seedlings outside during the day also gives them a healthy dose of full-on daylight (you can read more about how to avoid spindly seedlings here).

These are some seedlings that I've put outside for a dose of light on a warm day. The lid keeps them protected from the cold wind - but I'll take this off, too, when the seedlings get a bit bigger and stronger.

These are some seedlings that I’ve put outside for a dose of light on a warm day. The lid keeps them protected from the cold wind – but I’ll take this off, too, when the seedlings get a bit bigger and stronger. The masking tape on the side of the lid prevents it blowing off in the wind.

Your turn

What are you doing this month in your container garden? I’d love to hear.

 

21 comments… add one

  • Best time of year for me. Seedlings in the greenhouse are going for it. Since giving up my allotments after 50 years we use every little space around our bungalow. In the side garden I have planted first early potatoes Winston and salad potatoes Nicola. In part of the front garden I have planted International Kidney. Wilkinsons stores are selling 40 litre tubs for £3 so I bought six of these and planted them up with Charlotte salad potatoes in the back garden by the chicken house. Outside in the back garden there are spring onions and baby beets poking their heads up. The mint pots have started growing again after the winter. I have planted shallots in two places in tubs (old council paper bins). One comment I would like to make is regarding the use of old compost. I do use old compost after adding some nutrients, and after looking for Vine Weevil grubs which have a habit of living in last years compost. If they are left there then they will destroy any new roots. And of course the deadly slugs that seem to hide under a pinhead. Happy gardening.

    Best wishes,

    Mike Peirson.

    Reply
  • Excellent tips! I feel blessed that I found your site with so many tips and with a very similar weather. I live in northern Germany which makes it quite difficult to grow in our terrace because of these everlasting strong winds and grey skies. Last year was my first adventure growing our own greens and some tomatoes. I’d like to expand the varieties, but I don’t know what could be the best to grow. Strawberries were not that good last year (we had them in our wall, on felt containers I made myself following the same concept of Vertiflor. The plants grew very nice, not the fruit, have no idea why. The salads, chard and spinachs I had in wood containers (35x45x35 cm aprox.) were quite good. Lasted several months, chard and one salat until autumn! I already planted the seeds. Spinach is already growing fast, some salads on their way. I’ve been thinking to grow carrots or potatoes, but I have no idea if the containers of this size would do for these plants. I’m also growin indoors 2 lemons and 4 passion’s fruit. I’ve had to cut the passion’s fruit already 2 times! grows so fast but in a single branch. I’d like it to spread a bit and not to grow that tall. They are growing above the heater in my big livingroom window. And of course, herbs: Parsley, Coriander (Cilantro), Oregano, Thyme, Lavendel, Rosmary. Basil seems it won’t survive, too cold at the moment, I’ll have to buy another plant. I also have some sweet chili seeds (non-spicy) from my homeland (Venezuela) in a seeder indoors, and at nights I keep it above the radiator to keep them warm. In the next weeks or already in May we’re going to try with some new strawberry plants, and tomatoes again. Last year despite the cold, they were excellent! (and planted in one of the wooden boxes out side all the time). We also had yellow zucchini and red pepper bell. Those gave only 2 or 3 fruits each :( so I don’t know if I should try them again. I’ll keep updated with your posts. Great content you have and thank you for sharing all this info!

    Reply
    • Sounds like you are doing really great! In answer to your question about carrots, they should be fine in that size of pot. Home grown carrots taste delicious but I don’t grow too many because when you harvest them, they’re gone – where as many other crops keep giving you food over several weeks even months. Potatoes (1st earlies) grow quick and are fun – and your pot is just large enough for a few – a bit bigger would be better if you have one but not essential. Zucchini like big pots and lots of sun – then can be very productive. Peppers also like lots of sun. It makes me wonder – is your terrace getting much sun? I wonder if maybe not as the all the crops that did well for you like a lots of it. Very good luck in 2014!

      Reply
      • Hi Mark, thanks for your answer. In theory we should get tons of sun (all terrace is south oriented), as always as the clouds and storms you sent us from UK are not that many ;). Funny enough I just saw that you’re in Newcastle, so we live int he same line, straight to the east from you haha! (Flensburg, Germany). So I’ll be checking your updates and advices for sure!. I don’t think I’ll try with Zucchini this year. Needed a lot of space (I had only one plant and it produced only 2 small fruits), or Peppers, also 2 very small ones only. I prefer the idea of growing greens. They grow fast I can always crop the outer leaves, keeping the plant. Last year they lasted for months. I’ll give it a try with the Chinese greens you mentioned in one of your posts -need to go back to read again everything ;-). Ah also wanted to give it a try to the edible flowers you also mention in one of the posts, forgot its name. Thanks a lot for all your info!

        Reply
  • Hi Mark

    First, (and most importantly), thank you for this excellent site and for all the hard work you put into sharing your adventures in veg growing. It really is invaluable for someone like me just getting started. A top source of knowledge and inspiration.

    Second, apologies for the very long post. My partner, and most other people I know, think veg growing is a bit boring and middle aged and have very limited tolerance for me going on about it, so hopefully you won’t mind. Either way, I certainly appreciate being able to see what’s happening on your site when I have a moment.

    Third, if you’re interested, this is what I’m up to: I’m lucky to have a reasonable sized roof terrace on top of my flat in London. Much of it gets sun most of the day. Having never gardened in my life, I went up there in September last year having been away most of the summer and found that two pots left by the people who lived there before me had tomato plants growing in them that had produced a handful of ripe tomatoes (they must have been planted at least a year before as we have been in since November 2012, and I assume they must have grown from the seed of the previous year’s fruit). I ate them and was stunned by how good they were. I reasoned that if I could produce tomatoes that nice by accident, I should see what I could do with a little effort. I planted a family apple tree and fair bit of garlic at the end of last year. I have recently planted broad beans, mange tout, salad leaves, radishes, spring onions, carrots, and beetroot, all in containers up there. I also have some herbs, aubergine, chilli and tumbling tom tomato seedlings in a propagator on my windowsill. I plan to sow cucumbers and courgettes direct outside when it heats up a bit, and to plant gardeners delight and alicante tomatoes in the propagator in April to put outside later.

    Fourth, (if you have reached this far) I have a query: I am going away for two weeks from 12 April. I have no one I can bother to water regularly enough. I have bought an automatic irrigation system for the pots outside so they should be fine, but I am concerned about how to deal with the plants that are currently seedlings. I have a plan but don;t know if it is sensible. I have bought a mini pvc greenhouse (culticave) and intend to move what are now seedlings out into that and set up the auto-irrigation system to water them as well. Can I ask, do you think they will be strong enough by that point to deal with it (they are at the point now that I can just see the very beginnings of the first true leaves)? If not, do you have any other suggestions? If so, roughly how much water do you think they will need daily? Also, would it be advisable to put them out there during the day the week or so before I go away so that it’s not too much of a shock when they’re left overnight? Please don’t worry if you don’t have the time to get back, but any advice would be ace.

    Either way, all the best for your year ahead.

    Michael

    Reply
    • Hello Michael
      Thanks for writing and I LOVED your story about finding the rogue tomato. What a brilliant way to be inspired about growing. Thank you for sharing.
      Your tomatoes and aubergines are sensitive to frost and the ‘official’ date for the last frost in London is around the end of April. However, inside their mini greenhouse, fingers crossed they should be OK. I’d definitely put them out for a few hours each day before you go away to start acclimatizing them. Put them out on the warmer days to begin with and then slowly leave them for a bit longer and put them out on slightly cooler days, too.
      One solution to the watering might be capillary matting. It’s not something I’ve used myself but I know some people who swear by it and I think it might be just the thing for watering (but not over watering) seedlings. Do keep in touch – would love to hear how your roof garden evolves!

      Reply
      • Hi Mark

        Thanks for taking the time to get back to me. That’s really helpful advice. I’ll look into the capillary matting as well.

        I’ll definitely keep you posted on my progress.

        Michael

        Reply
  • Such a useful article! Loved reading it and I got many tips I can’t wait to put to use!

    I couldn’t help myself and I’ve had some tomatoes and pepper seeds sown indoors. Potatoes are chitting nicely and spring onions are doing well under polythene tunnel outside. Also, I have some garlic sown in autumn, it seems to enjoy the warmer days we had lately!

    Looking forward to you “what to do in April” article! :)

    Reply
  • Thanks for the help. I’m restarting gardening after a burnout nad the information is really helpful. And “nicely” done! Thanks, precious gardener! Have a good year! :-)

    Reply
  • PC been out of order for a while…had to fit a new hard disc drive…now back online….Saw the sun the other day (swoon), it was just a bit warmer here in the south east of the uk, but the north easterly wind is back today. I have given up my allotments and really enjoying growing at home in my restricted bungalow garden. At the moment I am up to date in the greenhouse with everything raring to get on with it.. There are still hard frosts in the morning so every evening I have to cover the little blighters with fleece and bubble plastic just in case. I don’t wan’t to bore you all but here is a list of my seedlings that are growing in the greenhouse at the moment. I have spuds (Foremost and Home Guard) Pots and pots of Comfrey taken from my allotment plants which have given me so many leaves over the years from a little bit of stalk with a leaf on it given to me years ago by an allotment friend..Tomatoes..Peppers..Early half Tall Brussels Sprouts (yum yum)..cabbages for the chickens and us..Carrot Autumn King and Nantes types..Roquette..Salad Bowl lettuce..Sage..Sweet Majoram..Dill..Basil….Outside under clotches I have Garlic..Shallots..and spring onions..and Spinach..and a variety of flower seedlings including Livingstone Daisies..African Marigolds..Sweet Peas..Petunias..Snapdragons..
    and Lobelia..the list goes on and on….just waiting for a bit of warmth now to make me happy..happy gardening to you all….

    Reply
    • Wow, Mike, what a wonderful selection of veg, my mouth is watering just reading. Do let us know how you get on – and would love to share a picture of your growing here later in the year if you’re have the chance and would be happy to send one. Now, let’s hope it gets a bit warmer!

      Reply
  • Hullo!
    This year I’ve started a bunch of cherry tomatoes, four types of pepper plus chilli (I am Hungarian, therefore a big fan of pepper), two types of turnips (green and purple), chives and basil. The peppers were slow to germinate, but they’re well on their way now, so I’m quite glad. Later on, I will sow some herbs directly in an outside container (I live in France and all the different herbs I would like to use in my kitchen, like marjoram, lovage, dill are difficult to find here). I do have two fairly sunless terraces and I’ve been strugling with the difficult task of growing herbs, but I haven’t given it completely up.
    Well, have a nice spring all of you lovely gardeners and best of luck to everyone with their veggies!

    Reply
    • Hi Monika, lovely to hear about your plans, thank you for sharing. I love the selection of veg you’re growing – and a great idea to growing the herbs you like that are difficult to find in your shops. I see what you’re saying about lack of sun – can be tricky! Most leafy stuff – like your lovage – should do OK. Have you found a nice sunny spot for your peppers and chillies? They love sun! T
      Thanks again for sharing.

      Reply
      • Hullo again!
        I do have sun for about a maximum of 4 hours during the summer. So I do have to start my vegetables early, otherwise autumn catches up with me and I don’t have much to harvest. Luckily, the weather is generally mild in Bordeaux. Next year, though, I’ll start a lot sooner on everything for a maximum of veggies and herbs, see how that works out.
        In any case, thanks for answering me and thanks for your website and useful tips. It’s highly appreciated in this corner of France.
        Have a nice evening!
        Monika

        Reply
        • Sun is good, Monika. Six hours or more is ideal for chillies – so you’ve set yourself a bit of a tough challenge growing them in four hours. Do let us know how it goes.

          Reply
  • I can see Evelyne’s enthusiam for the furure project. Can’t wait for the snow to go.

    Reply
  • What a lovely website! This year i’m turning my council flat landing into a vegetable and herbs growing patch.It was snowing this morning, I’m glad i waited.

    Reply
    • Love the sound of your project, Evelyn – would love to hear how it goes. Do you get much sun on your landing?

      Reply
      • thank you. I’ve only just managed to catch up with the course. 4 hours of sunshine is all i’ve got! I’ve decided to plant runner or french beans, the gardener’s delight seeds you’ve sent, carrots, kale (the Cavelo nero looks nice), herbs and salads. I’ll also give growing peas inside a try. I like plants who seed or can been grown with cuttings. Looking forward to the course.

        Reply
  • I have had allotments for over 50 years now, but have the dreaded arthritis for my trouble. Never mind, once a gardener always a gardener. My back garden is full of containers now ready for planting. Luckily I brought one of my greenhouses from the allotment (8′x6′) last year and I have seedlings growing. I have grubbed up the Rosemary bushes from the side garden and this will be used for my spuds as well as the containers in the back garden. I still have a good compost heap at the allotment which I can use as I have chooks at home here. I am looking forward to this month as there are lots of seed to sow. This morning when I woke up at 4am it is snowing, only about 2″ deep at the moment.

    Mike Peirson

    Reply
    • We have snow here, too, Mike. Loved hearing about all your containers, and clever move to bring a greenhouse to your garden – so handy for getting those seedlings of yours off to a good start. I’ve just managed to get hold of some plastic from an old poltunnel & hope to use it to rig up something similar in backyard. Happy seed sowing! Mark

      Reply

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