How to Know the Right Time to Harvest Cowpea

How to Know the Right Time to Harvest Cowpea

Early in my farming life I lost a good cowpea crop twice in the same way, and the two losses were opposites. The first year I was impatient. I saw the first brown pods on a Monday, got excited, and harvested the whole field that week. Half the pods in my sacks were still plump and green inside. The beans shrivelled as they dried, and they weighed far less than I had counted on. The second year I swore I would not make that mistake again, so I waited. I waited a little too long. A week of afternoon storms came through, the dry pods burst open in the field, and I picked up beans from the soil on my knees for days.

Harvest timing in cowpea looks easy and is not. The crop does not ripen all at once, so there is no single perfect day for the whole field. After thirty years I have a few simple checks that tell me when to pick, and I want to share them with you.

The short answer

Harvest cowpea for dry grain when the pods have turned from green to yellow or tan and then brown or straw coloured, feel dry and papery, and the beans inside are hard and rattle when you shake the pod. Because most varieties ripen unevenly, pick in two or three rounds, taking only the dry pods each time, and do it in the cool of the morning. For fresh green pods or fresh shelled beans, pick earlier, when the pods are full and plump but still green, usually about two to three weeks after the flower fell. The right moment depends on what you want the beans for, so decide that before you walk into the field.

What most farmers get wrong

I made every one of these mistakes, so I say this kindly.

They harvest the whole field in one day. In most improved varieties, pods mature over a stretch of one to three weeks or more. If you wait until the last pod is dry, the first ones have already split and dropped their seed. If you pick everything when the first pods are ready, you collect a lot of green, immature pods.

They go by the calendar and not the plant. The number of days to maturity printed on a seed packet is a guide. Weather, soil and planting date can shift it by a week or more. The pods tell the truth. The packet only estimates.

They harvest at midday. Pods dry and crack in the afternoon heat, and many of them shatter right in your hand. The seed ends up on the ground, and the field takes a share you never get to count.

They wait too long because the leaves are still green. Many cowpea plants keep their leaves green while the first pods are already drying. Do not wait for the whole plant to go brown. By then you may have lost a lot of beans.

They confuse a dry pod with a dry bean. A pod can look brown outside while the bean inside is still soft and full of moisture. Always open a few and check.

Know what you are harvesting for

Cowpea gives you three different products, and each has its own right moment.

If you want fresh green pods to cook like green beans, pick when the pods are young, still tender and bright green, before the seeds have fully swollen. This is usually about one to two weeks after flowering.

If you want fresh shelled beans, pick when the pods are fully plump and the seeds have filled out, but the pod is still green or just starting to change colour. The beans are soft, moist and full sized, usually about two to three weeks after the flower fell.

If you want dry grain for storage, seed or sale, pick when the pods are dry and the seeds are hard. That usually comes about three weeks or more after flowering, depending on the variety, the weather and the soil moisture. Most of this article is about this third case, because that is where most farmers lose the most money.

The signs I look for in the field

Colour is the first clue. A green pod ready for dry harvest will turn yellow, then tan, then brown or a pale straw colour. Some varieties turn purple or dark before drying, so learn what your own variety looks like when it is truly ready. Do not trust colour alone, because pods can change colour before the seed is fully dry.

The feel is the second clue. A mature pod feels dry, light and papery in the hand. If it still feels fleshy, thick or cool, it needs more time.

The sound is the third. Shake a pod beside your ear. A dry pod rattles, because the beans have shrunk and hardened and move freely inside. A pod with no rattle usually still has soft, moist seeds.

The bean is the final test, and the one I never skip. Open a handful of pods from different parts of the field, and look at the seed. A ready bean is hard, fully coloured for its variety, and resists the pressure of your thumbnail. Bite one. It should be hard and crack sharply, not dent like soft clay. A bean that is still soft, or that shows a wet green tint, is not ready.

The plant gives a few more hints. Lower leaves yellow and begin to fall, and the first pods dry while others higher up are still filling. When about two thirds to three quarters of the pods on most plants have dried and turned brown, I start my first round of picking.

Step by step: how I harvest

Step 1: Decide your plan before the pods are ready

Know what you are harvesting for, and prepare for it before the pods mature. Clean a drying area, such as a tarpaulin or a swept concrete floor. Gather clean sacks and containers. Check the weather forecast for the coming week, because rain is the biggest threat at this stage. A dry week in your favour is worth far more than a few extra days of waiting.

Step 2: Start checking about three weeks after flowering

Once the first flowers have turned into full pods, begin walking the field every two or three days. Open a few pods each time. This habit, a few minutes in the morning, is how I catch the first ripe pods before they split.

Step 3: Pick the first round when most of the early pods are dry

When the first batch of pods is dry and brown and the seed is hard, pick only those. Leave the green and yellow pods for the next round. Use both hands, and snap or cut the pods cleanly at the stalk, taking care not to pull off flowers or young pods still developing higher on the plant. Place them gently in a basket or open sack, not in a sealed plastic bag where trapped moisture can encourage mould.

Step 4: Pick in the cool of the morning

Early morning, after the dew has dried but before the heat builds, is the best window. The pods are slightly tougher then, less likely to shatter, and you lose far fewer beans. If the morning is wet, wait until the pods have dried. Never pick wet pods and bag them, because they will heat up and rot.

Step 5: Repeat every week or so

Come back every five to ten days and pick the next batch of pods that have matured. Most improved varieties need two or three rounds. Some farmers wait until most of the pods in the field are dry and then harvest everything in one go, and that works for varieties bred to ripen together, but it is risky with ordinary types because of shattering and weather.

Step 6: Dry the pods fully before threshing

Spread the picked pods in a thin layer on a clean tarpaulin or a concrete floor in full sun. Do not dry on bare soil, because the pods pick up moisture, dirt and insects. Turn the pods several times a day. Depending on the sun, this usually takes a few days. The pods should be brittle and crack easily when you press them.

Step 7: Thresh gently, then dry the beans again

Thresh by beating the dry pods lightly in a sack or on a tarpaulin with a flexible stick, or by trampling them gently on a clean surface. Hard beating cracks the beans, and cracked beans store badly and attract weevils. Winnow the beans in a light breeze to remove husks and trash. Then spread the beans out to dry again for a day or two, until they are properly hard and dry.

For safe storage, you want the beans at around ten to twelve percent moisture. If you do not own a moisture meter, use the bite test, and a salt test in a closed glass jar: if the salt stays loose and free flowing after a few hours, the beans are likely dry enough.

Step 8: Store properly right away

Harvesting on time is only half the battle. Clean out the broken seeds, and put the beans in airtight containers or hermetic bags filled to the top. Poor storage can erase a good harvest within weeks, so give the last step the same care as the first.

What to do if rain is coming

Rain at harvest is one of the most stressful moments of the season. If dark clouds are building and many pods are already dry, it is better to pick the dry pods now and finish drying them under cover than to risk losing them to shattering or mould. Spread them in a thin layer on a raised surface under a roof or in a well ventilated room, and turn them often. Do not pile wet pods in a sack. If pods get soaked while still on the plant, do not panic, but do not leave them there for long. Wet, standing pods can sprout in the pod or turn mouldy, so pick and dry them as soon as the weather clears.

Warning signs you are harvesting too early or too late

Too early shows up as beans that shrivel and wrinkle as they dry, a lot of green or soft seeds in the sack, light bags that weigh less than you expected, and poor, uneven germination if you use them as seed. Too late shows up as pods that split open in the field, lots of beans on the ground, seeds with holes from insects that started feeding before harvest, dull or mouldy beans after rain, and sprouting seeds in wet pods.

If you notice these signs in one harvest, take note. Adjust your timing the following season, because the field has just taught you something for free.

What I would do differently if I started again today

If I were beginning my first cowpea harvest again, I would plan the harvest before I planted the seed. I would choose a variety known for ripening fairly evenly if I wanted to harvest in fewer rounds, and I would plant so the harvest window falls into the drier part of the season.

I would open a few pods every two or three days from the third week after flowering, and I would trust the beans and the pods over the calendar.

I would make sure my drying area and my sacks were ready before the first pod turned brown, instead of scrambling in a rainstorm.

I would pick in the morning and in rounds, without exception.

And I would keep notes on the dates of planting, first flowering, first round and last round of harvest, and the weather. After two seasons, those notes will tell you your own field’s calendar better than any seed packet can.

Frequently asked questions

How many days after planting is cowpea ready to harvest?
For many early improved varieties, dry pods are ready roughly sixty to ninety days after planting, and the first green pods can be picked sooner. Medium and late varieties take longer. Check the maturity period given for your variety, and always confirm with the pods themselves.

How do I know cowpea pods are dry enough to pick?
The pods turn yellow, tan or brown, feel papery and light, and rattle when shaken. Open a few and check that the beans are hard and resist your thumbnail. If the seeds are still soft or have a green tint, wait a few more days.

Should I harvest all cowpea pods at the same time?
Usually not. Most varieties ripen unevenly over one to three weeks, so picking in two or three rounds, taking only the dry pods each time, gives the best yield and the least loss. Some varieties bred to ripen together can be harvested in one pass.

What is the best time of day to harvest cowpea?
Early in the morning, once the dew has dried and before the heat builds. Pods are less brittle then, so fewer split and shatter in your hands.

Can I harvest cowpea leaves and green pods before the dry harvest?
Yes. Many farmers pick young leaves for cooking and tender green pods for fresh use. Take leaves lightly and only from a few plants, because heavy leaf picking can reduce your later dry grain yield.

The one thing to bookmark

The calendar guesses, the plant tells the truth, so open the pod, hear the rattle, bite the bean, and pick only what is ready.