HOW TO GROW BROAD BEANS
By David Marks
Broad beans have been cultivated for thousands of years and the reason for this is simple, they are very nutritious, they are easy to grow and they produce a large crop for the area they occupy. The very best broad beans are those just slightly smaller than the average man’s thumbnail, at this size they are sweet and tender with a thin skin.In many areas of the UK they can be sown in open ground in autumn and this will produce an early crop in late spring or early summer. Success for autumn sowings depends on where you live in the UK and how wet / cold the winter weather is. Our guide below gives very specific advice for your area of the UK.
QUICK CALENDAR FOR GROWING BROAD BEANS
Correct timing is probably the most important factor in sowing broad beans and lumping all areas of the UK together (as most websites do) will not give you the correct sowing dates. Click here to adjust ALL dates in this website to be correct for your area of the UK and Ireland. If your area of the UK is too cold for autumn sowing it will tell you below.
Sow seeds outside in autumn – the third week of October
Sow seeds in pots for spring planting - the last last week of February
Sow seeds outside in spring - the last week of March
Transplant pot grown plants outside - the last week of March
Start to harvest Broad Beans approximately - the second week of June
Most soils are suitable for growing broad beans but if you are sowing them in autumn a free-draining soil is important. This will allow water to drain through the soil and stop the seeds from rotting. Although broad beans prefer cool conditions it is important to grow them in full sun or partial shade because they will have finished cropping well before the July and August heat sets in.
If the soil is fertile at planting time your broad beans won't need feeding again. For spring sown broad beans scatter a handful of fish, blood and bone in the soil per plant when planting. For autumn sown broad beans scatter a handful of fish, blood and bone in the soil around each plant in spring time (April) and gently work it into the soil surface with a trowel.
Depending on the height of the variety you are growing and conditions in , wind may be an important factor. It's always best to choose a site which is at least partly protected from the wind. Click here for details further down this page on how to support broad beans.
Autumn sowings are best made directly into ground in the third week of October . At this time of year the soil will still be about the correct temperature for germination. The two major problems with autumn sowing are cold and water-logging. Whilst you may be able to predict the temperatures with some accuracy, the amount of rain which may fall before spring is almost impossible to predict. Water-logging will cause the seeds and seedlings to rot.
To help you decide if autumn sowing is an option in your area consider the diagram below showing average soil temperatures in the UK. The majority of areas in the UK will fall somewhere between the blue and red lines. The chart shows the average of day and night time temperatures combined and you can assume that the day time temperature is about 2°C higher than the averages shown below.
The minimum temperature at which broad beans will germinate is 7°C / 45°F. If cloches are in place, or the ground is covered in plastic, the soil temperature will be approximately 2°C higher than shown in the above diagram, the ground will also be drier reducing the risk of the seeds rotting. The soil temperature is the key to sowing broad beans in autumn. If the temperature is high enough for just a couple of hours, the seeds will start the germination process.
For spacing and depths to sow broad beans see the paragraph Spring Sowing Direct in the Ground below. Although many books and gardening websites recommend autumn sowing, our experience is that in many winters the seeds fail to grow and even when they do the advantages over spring sown seed is almost indiscernible.
SPRING SOWING IN POTS
Only do this if you can provide cool (but not freezing) conditions for the seeds to germinate and grow on. If the seedlings are grown on in warm conditions the plants become leggy and very prone to damage when planted out. A cold frame or unheated greenhouse is ideal as is an unheated room or against the outside wall of a heated house out of windy conditions. Sow the seeds in the last last week of February and transplant them into open ground in the last week of March.
Fill a 7cm / 3in pot with multi-purpose compost and stand in shallow water for half an hour. Use a plant marker to make a hole in the compost about 4cm / 1½ deep and drop the seed in - it's not important which way round the seed goes. Fill the top of the hole with compost and gently firm the surface of the compost down.
Mark the pots with the variety sown and the date. Place the pots in a cool position (in or out of light). The ideal soil temperature for germinating broad bean seeds is about 12°C / 54°F but anywhere between 7°C / 45°F to 15°C / 59°F will give good results.
As soon as the seedlings appear above the compost make sure to move the pots to a position which gets lots of light and is also cool, a temperature around 12°C / 54°F is ideal for growing on young broad bean plants.
SPRING SOWING DIRECT IN THE GROUND
This is a good method for almost all areas of the UK. Seed should be sown in the last week of March .
Sowing broad bean seeds is simple. First the ground should be well dug to allow good drainage. If the soil is poor add well-rotted compost or a couple of handfuls of blood fish and bone fertiliser to every square metre / yard.
Broad beans have a very good germination rate so it's only necessary to sow one seed for every broad bean plant wanted. Sow a couple more seeds at the end of a row just in case one or two plants don't grow.
For dwarf varieties sow seeds 15cm / 6in apart, for taller growing varieties sow 23cm / 9in apart. Sow the seeds about 6cm / 2½ins deep lightly covering the seed with soil and lightly firming it down. Water well if conditions are dry.
If you are sowing more than one row then it is theoretically possible to have the rows 23cm / 9in apart. That is fine if you limit yourself to two rows. If you are sowing more than two rows then you need to allow more space between every second row (60cm / 2ft) so that you can walk down the rows and harvest your crop.
We have a strong preference for the dwarf varieties of broad beans because they don't need any support, taller varieties do. If you need to create supports then simply set stakes into the ground along each side of the row and tie a couple of string lines along the row supported by the stakes.
Broad beans are generally easy plants to grow without any special needs. When the pods start to grow on the lower part of the plant it's a good idea to pinch out the growing tip to help the pods grow well and also to reduce the severity of any attack by aphids.
Broad beans have two methods of pollination, important to know if you grow them in a greenhouse / polytunnel or under cloches. Their primary method is self-pollination, in other words they do not need insects to produce a crop. However, they can also be pollinated by insect activity and will produce the best crop when pollinated using both methods.
So, if you provide cloche protection early in the year it's best to remove the cloches as soon as flower buds start to appear. This will allow bees and other insects to get at the flowers when they form.
HOW TO SUPPORT BROAD BEANS
Taller varieties of broad beans will need support and even some of the shorter varieties will need support in windy conditions. This is very easy to do if you follow our instructions below.
Insert a cane deep into the ground at each corner of the area where the beans are to be grown. Tie one or two rows of string around the corner posts to enclose the broad beans. This applies equally to a single row or a block of the plants. If using one row of string, place it about 60cm / 2 foot high.
Nothing stronger is required, this will be enough to provide support to stop the plants toppling over. The string / canes can be put in place at any time before the plants reach 60cm / 2 foot high. See our page on broad bean varieties here for an estimate if a particular variety will require support or not.
POLLINATION OF BROAD BEANS
Most broad beans are partially self-fertile but you will have a much better crop if insects pollinate them as well. This varies depending on the variety. We explain below how they can pollinate themselves and some problem areas.
As a broad bean flower develops, the stigma inside the flower becomes taut and it is also bent over. Insect activity in the flower will cause the stigma to spring open onto the pollen allowing fertilisation to occur. In some cases, where there is no insect activity, the stigma will ripen and spring open as a result of wind movement. Sometimes it happens and sometimes it doesn't which explains why poor pollination can occur.
Some bees have become lazy in recent years and instead of entering the flower from the front to get at the nectar, they drill a small hole at the base of the flower and get the nectar from there. This type of bee activity is not so efficient as far as pollination is concerned.
Another problem with broad bean pollination is that different varieties will easily pollinate each other if insects are allowed to go between the varieties. This will often result in pods which are not true to type.
WHEN AND HOW TO HARVEST YOUR BROAD BEANS
Broad beans are best harvested when they are young and about the size of half an average thumbnail. At this stage the beans will have soft and tender skin and the flesh will be sweet and delicious.
Many beginners who have not grown broad beans before have asked the question, "does a broad bean plant produce ore than one picking of the crop throughout the year?". The answer is they only produce one picking each year however not all the beans on a broad bean plant mature at the same time.
They ripen earliest at the bottom of the plant. The amount of pods (each pod contains 8 to 10 beans) per plant is very variable depending on the variety but around 15 to 20 pods is a an average amount.
When your broad beans have finished cropping they can be dug up and placed on the compost heap. In their place there is still time to sow some lettuce, radish and beetroots. The beetroot may not grow to full size but they are delicious when harvested young.
As a guide broad beans should be ready for harvest around
the second week of June
although this will depend on when the seeds were sown and the weather conditions. Autumn sown seeds will tend to be ready a couple of weeks earlier compared to spring sown seeds.
Broad beans ready for harvest
To harvest the beans, twist the pod and gently pull the stem until it is removed from the plant. This can be a bit tricky some times because the stem holding the beans to the main stem can be quite tough. Don’t pull too hard, it can pull the plant out of the ground. If the stems are tough then a small pair of scissors is a very good alternative.
GROWING BROAD BEANS IN CONTAINERS
Broad beans are not an ideal vegetable to grow in containers however given the right variety and a large container they can be successful. The container should be at least 30cm / 1ft deep to allow the roots sufficient room. The best dwarf variety to choose is definitely The Sutton. Cultivation is the same as for growing in open ground although more watering will be required especially in warm and dry weather.
One trick which significantly reduces the need for constant watering is to place a layer of small stones or wood chip on the surface of the soil in the container. This works very well, far better than you might expect.
RECOMMENDED VARIETIES OF BROAD BEANS
We have dedicated an entire page to reviewing large number of broad bean varieties which can currently be grown in the UK. Click here to go there now.
SAVING BROAD BEAN SEEDS
Broad Bean seeds will keep well for three or four years if stored in cool, dry and dark conditions. They are ready for storage when the pods turn brown and are “crispy” whilst they are still on the broad bean plant. The broad beans inside the pod will be wrinkled and hard. Normally I would test out the hardness of one bean pod about three weeks after the crop has been harvested.
If the beans are not totally dry and hard, wait another week before testing with another pod again. Warm and dry weather speeds up the process whereas cold and wet weather slows it down. Err on the side of leaving the beans for a longer rather than shorter time – as long as the weather is not very wet they will remain viable on the plant for quite some time.
As with all seeds, do not bother saving seeds from F1 varieties of plants, they will not come true to type and are likely to be a very poor second to the original plant. If you want to know more about F1 seeds,click here. Be aware that broad beans will very easily cross-pollinate with other varieties of broad beans resulting in a plant the next year which may well be a cross between two varieties.
Cross pollination will occur the nearer the two varieties are to each other. This is not normally a problem for the average gardener.
Correct storage of the seeds is essential but easy. Place them in a paper bag such as an envelope and put them in a place which will be dry, dark and cool. Stored seeds do not appreciate being stored in conditions where there are large temperature variations.
PESTS AND DISEASES OF BROAD BEANS
Broad Beans are very strong growing plants and suffer from very few pests and diseases in our experience. The only pests you are likely to suffer from are aphids and this a very common occurrence. Spraying is not really an option because the beans will be harvested soon after any spraying occurs. It is worth while pinching out the growing tips as described in the care section above. The aphids love the growing tips and if you pinch them out it will remove their first point of feeding.
If aphids do attack then follow our advice in our page onaphids.
Damage to the leaves of broad bean plants is most likely due to pea / bean weevils. They tend to leave notches in the edges of the leaves. They can severely damage young broad bean plants but larger plants can normally outgrow them. See our page on
vine weevil which is almost the same pest and the advice given applies to both.
Blackened tips or edges to the leaves is, in most cases caused by frost damage. Plants started off indoors and then planted out (or into an unheated greenhouse) too early withouthardening them off are the most vulnerable. Normally they will grow through the damage when the weather warms up.
There is some doubt as to whether broad beans benefit much from crop rotation. We discuss this in detail on our crop rotation page which can be found here.
END OF ARTICLE
COMMENTS / QUESTIONS LEFT BY OUR READERS
|Date: 26 February 2021||From: Katharine|
|QUESTION: We sowed broadbeans and peas outside under a cloche in November. Most are now several inches tall and some are nearly touching the cloches. We’ve taken the ends off the cloches for air to circulate – should we remove them altogether? There was a frost last night.
ANSWER: Many gardeners successfully grow broad beans from a November sowing without using cloches.
When they get to the height where they actually touch the top of the cloches (sounds like that will be soon), would remove the cloches.
A frost down to -3C will not damage broad beans or peas which have been hardened off. Below that, down to about -5C they will survive with the possibility of some frost damage. But they will recover.
By keeping the ends open for a week or so, you have effectively hardened the plants off. The problem with the plants touching the top of the cloche is that damp and moisture may accumulate on the upper leaves increasing the risk of fungal diseases.
Be aware of the danger of too much heat as well as a frost. March can be warm some years and peas and broad beans can suffer under cover on warm days. Better a moderate frost with no cloche protection compared to a few very warm days with cloche protection.
|Date: 16 January 2021||From: Nicola H|
|QUESTION: I sowed bean seeds in the autumn and they germinated well. They have survived some snow and really low temperatures recently. They still seem to be healthy, should I fleece them or can I assume they will be ok?
ANSWER: Well done. I definitely would not fleece them. That will trap in moisture which will encourage diseases. If they have survived this far you have every chance of a healthy crop.
|Date: 10 August 2020||From: Sue H|
|QUESTION: My broad beans looked healthy but recently the foliage has discoloured and it spread quickly. Looking online, I think it’s rust. Is it ok to carry on harvesting the beans and then cut foliage down and destroy or should I destroy the lot now! Also, will it be ok to leave the roots in the ground for the nitrogen or must everything go? Lastly, can I sow different things in the same space?
ANSWER: If the beans inside the pods look OK then they should be fine to eat.
I would remove the roots for two reasons. First, although they do fix nitrogen, the plants use that nitrogen and there is almost nothing left when the plant has produced beans. It’s a gardeners myth that the roots add nitrogen to the soil. Second, I’m not sure at this moment if rust overwinters in the soil. I wouldn’t take the chance and I would burn them, don’t put them on the compost heap.
Try sowing beetroot after harvest and expect tender small beets before winter. Radish will also grow in the same space.
|Date: 18 July 2020||From: Louise|
|QUESTION: I have picked one harvest of beans from the plant and now there are more short shoots with flowers on. Should I cut down the previous old stems or leave them? There are no more flowers on them.
ANSWER: I doubt very much that you will be able to harvest any more broad beans this year. They are a spring to early summer crop.
If you have no more use for the space they occupying then I would cut away the old stems and leave them to rot in the ground. You could also dig them up and put them on a compost heap if you have one.
|Date: 14 July 2020||From: Doug|
|COMMENT: Broad beans are a favourite of mine. There is no need to pinch out the tops as long as you avoid using insecticide in your garden. Ladybirds will wipe out blackfly within 24-48 hours or so. Same with aphids generally. I like the beans mature. They freeze well.|
|Date: 14 July 2018||From: Chris|
|QUESTION: Broad beans have now finished and were very good. I’ve read contradicting
articles about whether to leave the roots in the ground for nitrogen fixing but others that say this is outdated thinking and
that once the beans have podded up all the nitrogen has been used. What is your advice?ANSWER: Yes, once the beans have been harvested the roots will have almost zero nitrogen in them.
I dig them up and if the plants are healthy chuck them on the compost heap.
|Date: 18 February 2018||From: Jenny|
|QUESTION: Planning to do spring planting of beans directly in soil. Will they suit a
fairly shaded spot or do they need lots of light? Trying to organise what putting in each bed and running out of ideas for the semi shaded area.ANSWER: Broad Beans do prefer a sunny position. One reason is that they grow earlier in the year compared to many crops and the sun is not very strong initially.
|Date: 15 January 2018||From: Margaret|
|QUESTION: Can I grow broad beans in the same place I grew them last year? It was
a good position in relation to other plants, but I’m not sure if it is best to rotate things.ANSWER: All vegetables benefit from rotation. However, the bean “family” of vegetables, including the broad bean, are the least likely to suffer if you don’t rotate them. So certainly give it try in the same position again this year but I would then rotate in 2019.
|Date: 18 October 2017||From: Tom|
|QUESTION: I live in Canberra Australia and have produced a healthy crop of broad beans.
One possible problem is that some of the beans pods(?) have black tips, not on the leaves or the bean itself. Do you have any ideas on what it might be?ANSWER: If the pods have formed OK with beans in them then I wouldn’t worry. It is probably caused by a short spell of colder than normal weather when the pod was forming. If the pods are small and have turned black without any beans in them then the problem is that they have failed to pollinate.
|Date: 2 June 2017||From: Bryan|
|QUESTION: Now my broad bean plant has flowered but now the flowers look like they are
dying they are going brown and falling off (could all be natural) any help would be greatly appreciated! Also when should I harvest them as on your website (I know everywhere is different) it says harvest around the start to middle of June but I’m not sure if they will even be ready then. Help please.ANSWER: That’s natural for the flowers to die, they will then produce broad beans where the flowers were. The flower’s job is to attract pollinating insects, allow them to pollinate the plant and then their job is done. Harvest dates depend on a lot a factors, expecially when the seeds were sown / planted out so don’t be concerned. Harvest the beans when when look a reaonable size.
|Date: 27 March 2017||From: Bryan|
|QUESTION: Is it beneficial to soak peas and broad beans before planting?
ANSWER: The germination rate for broad beans and peas is good so I never soak them. It just seems to be another task without any real benefit.
|Date: 26 March 2017||From: Joy M|
|QUESTION: Someone told me my broad beans had rust last year and they pulled them up -is it likely they would be infected this year? How should I clean the soil? It is a raised garden
ANSWER: The spores of broad bean rust may over winter in plants in soil and theses are likely to re-infect this year’s broad bean plants. In a raised bed garden it would be a good idea to remove the top 15cm / 6in of soil / compost and replace with new compost to avoid re-infection unless you are sure the soil is clear of all plants.
|Date: 23 January 2017||From: Matthew|
|QUESTION: I’m planning on growing my broad beans on my brassica bed this year before
transplanting the winter cabbages and broccoli. Does this sound suitable? Will the beans be finished in time?ANSWER: For average temperature areas of the UK the sowing and planting times would normally
be as follows:
Broad Beans – sow outside early March
Broad Beans – plant out pot grown plants late March
Broccoli sprouting – sow seed in pots / seed bed late April early May depending on variety
Winter Cabbage – sow seed mid to late May
Broad Beans – begin to harvest early to mid June
Broccoli sprouting – transplant to final position early July
Winter Cabbage – transplant to final position late June / early July.
So, weather conditions permitting, you should be OK.
My only reservation is that you propose to plant brassicas in the same bed for two years running. This would increase the chance of diseases. It all depends on how strictly you want stick to the rules of crop rotation.
|Date: 30 October 2016||From: Elizabeth T|
|QUESTION: I have grown some broad beans In my unheated greenhouse. Can I plant them out now?.
ANSWER: Yes you can. Just as a precaution I would take them out of the greenhouse for a week to fully harden them off. Put them where they will be exposed to some wind but take them back in temporarily if it gets very windy.
|Date: 7 August 2016||From: Joy|
|If there is only one advantage to an autumn sowing, it’s having one less thing to do when the garden gets busy in spring.|
|Date: 23 October 2016||From: James|
|QUESTION: When you pod broad beans should they have a black line on one end?
ANSWER: Some do and some don’t, it all depends on the variety. I don’t have a picture of one that does but see this link here for a good picture of broad beans with a black line at the end of each bean.
|Date: 13 July 2016||From: Jan C|
|QUESTION: Why are there no beans in my broad bean pods? They are big pods and look full, but when I picked them there was only one or no beans in them. The pods were about 6 to 7″ long. Any suggestions please?
ANSWER: There are a couple of reasons for this. The first is a lack of insect pollination. Sometimes the weather is too windy or cold when the flowers need pollination. There is not much you can do about this (other than hand pollination) and next year there may well be no problem.
The second reason is that the flowers have been pollinated but they have failed to set. The most common reason for this is that temperatures are too high. If you suspect this is the case, plant out / sow seeds slightly earlier next year to avoid the warm weather.
|Date: 25 March 2016||From: Jennifer Jenkin|
|I found the answers to all my questions on this website. Thanks|
|Date: 19 March 2016||From: Caroline M|
|QUESTION: I have pinched out the tops of my broad plant seedlings, 18cm tall with the thinking it would produce a stronger plant like in sweet peas. My mother told me that’s not a good idea and they won’t crop! have I ruined my plants?
ANSWER: It’s not something I’ve done myself so I can’t say for sure. I suspect that although you haven’t done the ideal thing, the plants will sprout new shoots below where you have pinched them out. Who knows, you may have discovered a useful technique that no one else has discovered. Certainly, don’t abandon them, I think all will turn out OK.
|Date: 14 March 2016||From: Peter L|
|QUESTION: I PLANTED MY BROAD BEANS IN JANUARY AND SOMETHING SEEM TO HAVE EATING ALL THE SEEDS UNDER GROUND
ANSWER: Mice or squirrels are the most likely culprits. The only measure I have heard of which works is to soak the beans in liquid paraffin before planting them.
|Date: 24 July 2015||From: Margot|
|QUESTION: I bought some broad bean plants from a nursery when they were about 12 – 18″ tall with flowers on. I’ve never grown them before but they have several pods on now about 3 – 4″ long. I planted them in June and all the plants are looking healthy with plenty of flowers and pods setting. I have pinched out the tops on the plants now but don’t know when to harvest the pods for maximum flavour and tenderness. I would prefer them small and young rather than older and more mature. Please advise. Thank you
ANSWER: The only way to get them at the stage you personally prefer is to open up a pod or two and see what size they are. Much depends on the variety and growing conditions. I would suggest opening up a pod when they are about 15cm / 6in long and take it from there.
|Date: 20 July 2015||From: Rob|
|QUESTION: Could you please tell me why my broad beans are only cropping from bottom of plant to middle and not all the way up?
ANSWER: That’s quite normal. I’ve just been down to my allotment and looked at my broad beans and my neighbour’s and the beans only go roughly half way up. Different varieties will produce beans slightly differently, some may well crop all the way up but not all.
|Date: 30 June 2015||From: Francis A|
|QUESTION: White flowers on my broad beans are being eaten; any suggestions as to what is eating them and what treatment is needed?
ANSWER: It’s unusual for the flowers on broad beans to be attacked, the only culprit that springs to mind are birds. They occasionally are attracted to them and leave tell tale rips in the flowers rather than eating them. Aphids are another possibility, they don’t actually eat the flowers but can distort the flowers to such a degree that they may look like they have been eaten. If that’s the case you will see what looks like black marks around the flowers and tips of foliage which is in fact just massed aphids.
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