Have you ever bitten into a sesame bagel or dipped into some hummus and wondered how to grow and harvest those tiny sesame seeds? When are sesame seeds ready for picking? Since they are so tiny, picking sesame seeds can’t be a picnic so how is sesame seed harvest accomplished?
Ancient records from Babylon and Assyria have attested that sesame, also known as benne, has been cultivated for over 4,000 years! Today, sesame is still a highly valued food crop, grown for both the whole seed and the extracted oil.
A warm-season annual crop, sesame is drought tolerant but does need some irrigation when young. It was first introduced into the United States in the 1930’s and is now grown in many parts of the world on over 5 million acres. All very interesting, but how do growers know when to pick sesame seeds? Sesame seed harvest occurs 90-150 days from planting. Crops must be harvested prior to the first killing frost.
When mature, the leaves and stems of sesame plants change from green to yellow to red. The leaves also start to drop from the plants. If planted in early June, for example, the plant will begin dropping leaves and drying out in early October. It still isn’t ready to pick, though. It takes a while for the green to disappear from the stem and upper seed capsules. This is referred to as ‘drying down.’
When ripe, sesame seed capsules split, releasing the seed which is where the phrase “open sesame” comes from. This is called shattering, and until fairly recently, this characteristic meant that sesame was grown on small plots of land and was harvested by hand.
In 1943, development of a high yield, shatter resistant variety of sesame began. Even as sesame breeding has soldiered on, harvest losses due to shattering continue to limit its production in the United States.
Those intrepid souls who do cultivate sesame seeds on a larger scale generally harvest the seed with a combine using an all crop reel head or a row crop header. Given the tiny size of the seed, holes in combines and trucks are sealed with duct tape. Seeds are harvested when they are as dry as possible.
Due to the high percentage of oil, sesame can turn quickly and become rancid. So once harvested, it must move quickly through the sales and packaging process.
In the home garden, however, the seeds can be collected prior to splitting once the pods have turned green. They can then be placed into a brown paper bag to dry out. Once the pods are completely dry, simply break up any seed pods that haven’t already split open to collect the seeds.
Since the seeds are small, emptying the bag into a colander with a bowl beneath it can catch them as you remove the leftover seedpods. Then you can separate the seeds from chaff and store them in an airtight container in a cool, dark location until ready to use.
Growing Sesamum indicum, or sesame, connects you with a gardening tradition older than the Bible.Today sesame is typically grown on a large scale for its seeds, but it still makes regular appearances in home ornamental gardens, where its fragrant white or pink blossoms attract butterflies and birds. Sesame takes a little work to sow in the spring, but once it's established, it needs very little care and even improves soil conditions in your garden.
Choose a location that receives full sun for all or most of the day. Sesame thrives when it can spend the whole season in full sun.
Plant in loamy or sandy soil that drains well and contains plenty of organic matter. If you don't have fast-draining or fertile soil, amend with sand or peat moss and compost to improve conditions.
Poke your finger into the ground to create a 1/2- to 2-inch hole. Scatter roughly three seeds in the hole and cover gently with soil. Space the plants anywhere from 6 to 18 inches apart. Don't worry too much about spacing because sesame seedlings will self-thin rather than crowd each other and compete for resources, according to the Thomas Jefferson Agricultural Institute.
Plant next to a wall, garden border or fence if possible to help protect the plants from storms and strong wind. Until the plants develop deep, strong roots, they're highly sensitive to wind and strong rain.
Water just before the soil dries out. Seedlings need regular water to grow, while mature plants need dryer conditions. Avoid overwatering, as sesame doesn't tolerate soggy conditions for long.
Harvest the seeds when the seed pods start to look dried out, but before they start to split open.
Sesame is commercially produced in desert settings, so when we say it’s drought tolerant, we really mean it. In fact, this is really the key to success with sesame seeds, as we will outline in the following guide on how to grow sesame from seed. Sesame is a tropical annual herb that grows to about 60cm (24″) tall. Its leaves radiate out from a stem that is square in cross section.
Season & Zone
Season: Hot season
Exposure: Full sun
Zone: Not hardy
Sow seeds indoors 4 to 6 weeks before the last average frost date. Transplant under cover a similar period after the last frost date. Remove the cover some time mid-May to early June, once the night time temperatures are warmer. The days to maturity is from transplant date, as these seeds do not respond well to direct sowing.
Lightly cover the seeds with sterilized, soil-less starter mix, and keep just moist until germination. Don’t keep the seeds in a highly damp environment, and be sure not to over-water the seedlings. Once they sprout, reduce watering to once a week until transplant time. Optimal soil temperature for germination: 21°C (70°F).
If steps are taken to increase warmth in and around the plants, they will be more productive. Try transplanting into a raised bed, or into the ground using black plastic mulch over the soil. Do not fertilize sesame plants, and avoid drip irrigation, as they really do like it dry. Plant fairly densely at 15cm (6″) spacing, in rows 60-45cm (24-36″) wide. Sesame is indeterminate, so it will continue to bloom and set seed capsules until the end of summer. Expect flowering to peak in July and August.
The tubular flowers of the sesame plant are highly attractive to honeybees, and are said to produce some of the highest grade of honey. The plants are relatively self-fruitful, so when the flowers open, the seeds are already fertilized. The seeds are produced in pods (seed capsules) that appear along the stem.
Around the end of August, some of the pods near the bottom of the stem (the first flowers that opened), may begin to show signs of ripeness. When ripe, the pods begin to split from the blossom end. Don’t worry if this doesn’t happen in the field. Before wet weather arrives, cut the stems at the base and gather them to dry some place that is flat — hanging them will cause the seeds to just fall out as the pods dry. As the plants dry, the foliage will darken and more pods will open from the base of the stem upwards. Once most of the pods have opened, bash them against the sides of a bucket to collect the dry seeds. The seeds are edible at this stage, and resist spoilage better than most nuts. They can also be toasted, pressed for oil, or ground into the paste known as tahini.
Sesame plants each produce quite a lot of seeds, but the seeds have little mass. From a 10 foot long, 2½ foot wide row, expect to harvest approximately 425g (just under one pound) of seeds.
Matures in 75-110 days. (Open-pollinated seeds)
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Your germinated sesame seedling, if you have taken good care of it and not allowed it to die, should flower about 6 weeks later.
So if you had it in a seed tray or small pot, I hope you remembered to pot it on as it grew.
The flowers are white to pale rose, depending on variety, which will be fun for you because you'll have no clue which variety you have grown, seeing as you just bought 'sesame seeds' for the kitchen.
The flowers develop in the leaf axils.
The leaves themselves vary depending on their variety. They can have different shapes, sizes and some will be evenly spaced and other alternately on the branches, again depending on type.
If you are lucky, yours will have leaves positioned evenly, opposite from each other.
This type produces more flowers, and obviously more flowers mean more seed capsules, which means more seed at the end of the day.
Sesame plants are self-pollinated, which means you don't actually need more than one plant for pollination to occur.
Insects can also cross-pollinate which means if you have two or more plants, you could have some interesting seed for planting next year.