Okra is a seed pod vegetable extensively used in salads, recipes, soups and stews because of its spicy taste. The pods can also be boiled or fried and eaten as a vegetable. The vegetable is a rich source of many nutrients, including fibre, vitamin B6 and folic acid.
The plant can be grown on a wide range of soils provided they are fertile and well-drained and in areas which are warm with moderate rainfall. If the soil is not fertile, compost manure should be applied. Okra is a fast-growing crop that takes only between 50-60 days to be ready for the first harvesting.
Kamini, Pusa mukhamali, Pusa sawani, parbhani kranti, Vaishali, Vagmi and Padmini.
Temperature. Okra is a tender vegetable that cannot tolerate low temperatures for very long but frosts are deadly. The optimum temperature range for growth is 240 to 300C, although okra is highly resistant to drought, it still requires considerable water for optimum growth and yield.
Soil. Okra grows best in well-drained sandy loam soils with high levels of organic matter and pH ranging from 5.8 to 6.5). It is difficult to achieve good stands when directly sowing seed in heavy clays. Be sure to choose a well-drained soil, since poorly drained soils may result in drowning of the plants.
Before planting, soil test each field to determine the correct fertility. Follow the recommendations from the analysis to prevent excessive plant vigor and poor yield. If no soil test is made, a general recommendation is to apply 11kg of nitrogen, 28kg of phosphorus (P205), and 28kg of potassium (K2O) per acre.
Seeding rate and spacing.
Prepare the land to ensure establishment of a uniform stand. Turn the soil in the dry spell so crop residues can decompose before the okra is planted. Early land preparation also allows time for weed seed to germinate, allowing for early cultivation to destroy young weeds.
Seed the okra to produce stands with plants spaced 45cm apart within the row (spacings can be closer when using semi-dwarf varieties) and 15cm between rows. Seeds should be planted to a depth of 5cm. To achieve the maximum stand, plant three to four seeds per foot and thin to desired spacing. Seeding at this rate will require 1kg of seed per acre. Soaking seed in water overnight helps hasten germination. Transplants will enhance earliness. Transplant at the three- to four-leaf stage.
Top dressing. Side dress with 9kgs of nitrogen when plants are 24-30cm tall and again 2 to 3 weeks later.
Crop rotation. Okra is very susceptible to damage from nematodes. To prevent a build-up of nematode populations, follow a crop rotation using corn or grass crops. Okra should not follow other crops that are highly susceptible to nematodes such as squash and sweet potatoes, which tend to increase nematode populations. To determine the nematode population in your field or garden, collect a soil or root sample and have it analyzed for nematodes by a reputable laboratory.
Mulching and Drip Irrigation
Polyethylene (black plastic) mulch can offer growers several advantages. Black plastic mulch increases soil temperatures, accelerating the growth rate of the plant. Additionally, black plastic reduces the severity of several common problems: soil compaction and crusting, fertilizer leaching, drowning of crops, evaporation of soil moisture, and growth of weeds. These benefits promote increased quality and quantity of yields and result in earlier yields especially when used with transplants. Although using mulch will increase production costs, those costs may be offset by increased profits from high yields realized. Drip irrigation systems must be used with plastic mulch.
Controlling Weeds, Insects, Diseases, And Other Pests
Weed control. Weed species infesting okra include annual grasses and perennial grasses. keep okra fields weed free, tillage offers good weed control for grasses. Avoid throwing too much soil directly against the okra stems, because doing so can increase incidence of stem rot.
Few herbicides are registered for weed control in okra fields. Using them improperly can damage your crop. Contact your local extension personnel or agronomist for right chemical selection and application guidelines.
Chemical control of insect pests of okra can be a problem because few insecticides are registered for use on this crop. Frequent pest scouting and use of cultural controls are advised to find pest problems early and make the crop less suitable for insect infestations. Insect pests of okra fall into two categories — foliage feeders and pod feeders.
Foliage feeders only cause economic damage (loss of yield) when pest numbers are high or when plants are young (or stressed). Foliage-feeding on well-established plants does not normally cause loss of yield because healthy plants can tolerate considerable loss of foliage before yield loss occurs. Tolerance of foliar damage increases with age of the plant and favorable growing conditions (that is, plentiful soil moisture, proper fertility).
Growers can manipulate some production practices to minimize insect damage to okra. First, ensure that plants have favorable growing conditions such as sufficient water and fertilizer, particularly when plants are small. Strong, healthy plants are better able to tolerate insect damage. Many insects over winter in debris and weeds, so removing these refuges in the fall after crops are harvested will reduce infestations the following spring. Also, weed control during the season around and in the field will reduce populations of many pest species, including flea beetles, blister beetles, and aphids. Early planting will reduce damage by several caterpillar species, because large populations do not usually develop until later in the season. Growers with small plantings may consider use of protective row covers early in the season to shield young plants from insect feeding.
Chemical controls. Very few insecticides are registered for okra because it is a minor crop and few companies can afford the increasing registration costs necessary to maintain a minor crop product. Therefore, frequent scouting and cultural controls are most important. Contact your county Extension agent for up-to-date recommendations on insecticides registered for use on okra.
Nematodes. Okra is infamous for its susceptibility to root-knot nematode damage. Nematode damage commonly causes irregular growth and reduced or delayed production. Okra plants damaged by root-knot nematodes are usually stunted and appear unhealthy with elongated, round swellings on both large and small roots. Okra should not be planted in an area known to have a high population of root-knot nematodes. If okra must be grown in an area where damage from nematodes is likely, then a nematicide should be applied prior to planting. Follow all label recommendations and restrictions when using these products.
Disease control. The most common disease of okra is blossom blight caused by the fungus Choanepbora cucurbitarum.
Blossoms -sometimes very small pods covered with a cottony growth tipped with black fungal fruiting bodies. These pods fail to develop. The disease is more severe during periods of very high humidity and particularly in partial shade. The best control would be to avoid over fertilization and planting in low areas or shady sections of a field. Also, avoid the use of overhead irrigation late in the day. Leaf spot-can be caused by a number of fungal pathogens. No fungicides are currently available for control of these diseases. The best control would be to follow a suitable crop rotation sequence and to follow a balanced fertilization program.
Most varieties are ready to pick 55 to 60 days after planting. Pods should be harvested when they 6-8cm long.
Generally, pods should be picked 4 to 6 days after flowering. Pods can be snapped off or cut. Cutting takes longer but produces a nicer product. You should produce 7000kgs of okra per acre on bare ground. Based on research, yields on black plastic can be two to three times greater than on bare ground.
Okra deteriorates rapidly and is normally stored briefly to hold for marketing or processing. Avoid bruising the fruits as they intend to lose water rapidly and this affect their quality. Large quantities are canned, frozen, or brined. Okra has a very high respiration rate at warm temperatures and must be promptly cooled to reduce field heat and subsequent deterioration.
- NB. This crop is new to Kenya and its production has not being adopted by many farmers for its knowledge is still spreading at a snail pace. Before growing the crop adhere to the guidelines as the crop is quite sensitive to growing conditions and other plant stresses.