It takes two growing seasons for a cauliflower to produce seeds. In the first, the plant makes the head. If the head is left unpicked, seed pods emerge from it the following summer. As the seeds ripen the plants start to dry out and the orange-brown color of the plant is the best sign of this.

The approaching maturity of the majority of seeds on a plant can also be confirmed by opening a sample of the oldest pods which will be the first to become brown.Many seed producers prefer to cut the ripening material by hand and place in windrows or on sheets to continue drying before extracting the seeds in stationary threshers.

 

Direct combining can only be done in dry conditions and care must be taken to minimize the loss from shattering.

 

 

 

Integrated soil fertility management

Deep, loamy, well-drained soils are needed for the production of cauliflower. The soil pH and fertili- ty should be carefully maintained as described for cabbage. Boron stress can cause stem cracking or browning of individual florets of broccoli and water-soaked areas in the stem and center of the branches of the curd in cauliflower. Both broccoli and cauli- flower are also sensitive to Mo defi- ciency thatis expressed as “whiptail” in which the leaf blades fail to ex-pand.

Nitrogen deficiency, the exposure of young cauliflower plants to low tem- perature or environmental stress, or the combination of both, can lead to buttoning in which the head or curd forms prematurely before the plant is fully developed. Cauliflower can de- velop “ricey” heads in which small white flower buds develop and the curd appears like boiled rice. This defect has been associated with spe- cific cultivars, high temperatures during curd development, rapid plant growth, and heavy applications of N. Blindness or lack of curd formation may have several causes including poor fertility, insect damage, genetic irregularities or cold temperatures. Cauliflower is also sensitive to mag- nesium (Mg) and manganese (Mn) deficiencies, which are expressed as interveinal chlorosis on the older or younger leaves, respectively. Soil tests and the management of soil pH are critical in the production of cauli- flower.

Deficiencies

1. Nitrogen 130 -170 kg/ha of actu- al nitrogen is required for successful cauliflower production. If manure is applied or legume sod is plowed down than the rate of nitrogen fertilizer is adjusted appropriately. About  half of recommended nitrogen is broad- casted and worked into soil prior planting. The remainder of nitrogen is applied in two side dress applica-tions. The first side dress application should be 7-10 days after planting and the second 4 -6 weeks later.If the sea- son is, very moist, a third side dress application may be used three weeks after the second application. Ade- quate nitrogen produces a dark green color in cauliflower leaves. Nitrogen deficient plant leaves are light green, eventually turning yellow and may be shed. Nitrogen is not generally recognized in soil test analysis sheets received from your soil lab
2. Phosphorous: A soil test will determine the level of phosphorous requirements. Broadcast or band any needed. Phosphate before planting and work in. Phosphorous is import- ant for root growth. A shortage of Phosphorous stunts plants growth.
3. Potassium: A soil test will de- termine the level of potassium re- quirements. Broadcast apply potash when its wet.In addition, work into the soil. Excessive potash may lead to increased tip burn (internal and/or external).Potash competes with calci- um for uptake from the soil and this is probably what causes the increased tip burn.
4. Magnesium: Olderleaves are the first to show deficiency signs, which include blotches of interveinal chlo- rosis.As the chlorosis intensifies, pur- ple blotches may be seen near the leaf margins. Deficiency is common especially on light acid soils where dolomitic limestone has not been applied. To avoid these prob- lems apply dolomitic limestone or add magnesium to the fertilizer. If theproblem occursduring the season, spray the foliage with Epsom salts (magnesium sulfate).
5. Sulfur: Early deficiency symp- toms appear as blotches of intervein- al chlorosis on the youngest leaves, In addition, the leaves may become reflexed. On sandy soils low in organic matter that has beenintensive- ly cropped, soil sulfate levels may be low. Application of gypsum should be consideredon these soils.Cauliflow- er crops have a high need for sulfur and have shown signs of deficiencyin many fields

 

Micronutrients

1. Boron: Boron deficiency may also lead to browning of the curd and has been associated with a condi- tion known as “hollow-stem”. Boron should be applied within two weeks of transplanting with a further one  or two sprays if the crop is growing quickly.
2. Molybdenum: Molybdenumde- ficiency is often induced by soil acidic reactions and the main symptom of the disorder is the malformed leaves, which are narrow, twisted, and hooked, if the deficiency is severe, re- sulting in whiptail. A spray of ammo- nium or sodium molybdate should be applied.
3. Manganese: An induced manga- nese deficiency may occur if too much lime is applied. The main symptom is severe mottling between veins, which retain their normal color. This may be corrected by applying manganese sulphate (5 kg per 1000 l of water). Several applications may be needed and a wetting agent should be used.
4. Potassium:Potassium deficiency which is also known as leaf scorch or marginal leaf burn can be corrected by applying muriate of potash at between 200 to 300 kg per ha.

Figure 1 Cauliflower seedlings layout in the field.

Source https://www.gardeningknowhow. com/edible/vegetables/cauliflower/plant- ing-cauliflower-seeds.htm

Regenerative Agriculture

Regenerative agriculture is an ideology and farming practice based on many years of scientific research and agro-ecological farming practices such as organic, biodynamic and permaculture. Regenerative agriculture works in harmony with nature, valuing animals and ecology. It increases biodiversity, builds and enlivens soils, protects the land from erosion and improves our ecosystems. It also aims to sequester carbon below and above ground in soil, plants and trees, reversing current trends of accelerating carbon emissions. Good practice creates competitive yields, provides jobs – safer working environments for farming communities – and importantly healthier, better tasting food.

 

Crop rotation: There are many benefits to crop rotation including the suppression of diseases, insects and weeds. In addition, crop rotation improves soil fertility because it is allowed to replenish naturally and soil structure improves because of the alternating between deep rooted and fibrous rooted crops. Crops within a family tend to be susceptible to the same pests, therefore rotation of non-susceptible crops (or groups) for several years allows all plant material to decompose and pest cycles to become broken. Without the presence of susceptible plant material, the number of disease and insect organisms will begin to diminish. Crop rotation aids in weed control because the growth habit of each crop differs, which causes a decrease in a weeds ability to compete for space. In addition, tillage practices and timing are different for dissimilar crops resulting in a decrease in the weeds ability to permanently establish. Another benefit of crop rotation for weed management purposes is with certain crops, there is a better chance at controlling different weeds. For example, in a broadleaf crop, grass control will be easier because of the use of grass killing herbicides and vice versa.

Intercropping: Intercropping is the cultivation of two or more crops simultaneously on the same field. It also means the growing of two or more crops on the same field with the planting of the second crop after the first one has completed its development. You can intercrop cauliflower with legumes and maize.

Land Preparation

Site   selection   and   soil   preparation:Good   soil preparation  is  important  when  planting  cauli- flower. The best way to determine your soil condi- tions are to have a soil test performed. Cauliflower requires a fertile, well-drained soil with a good water holding capacity and a pH range of 6 to 7. Working the soil to break up any hardpan, and incorporating manure or compost to a depth of 15 to 20 cm are nor- mally best recommended. If soil must be treated for root-knot nematode, this must be done after the soil is prepared, and allowed an interval of 2 to 3 weeks after  treatment  before  planting.Seedbeds  for  trans- plants should be irrigated to ensure adequate growth after  germination.  The  soil  on  which  seedbeds  are to be made must be friable, well drained, and free of noxious weeds. Soil pH should be in the range of 6.0 to  6.5,  with  soil  fertility adequate  for  plant  growth but not excessive. Seeding depth should be 1.5 to 3.0 cm  (0.5-1.2  inches),  depending  upon  available  soil moisture  and  prevalent  soil  temperature.  Seeding should be deeper in dry conditions or in soils that are prone to drying out. The optimum distance between seed is 1 to 2 cm (0.4-0.8 inches). Seed should provideproduce 3,000 transplants.

Sowing and nursery care Cauliflower is propagat- ed by seed, which are sown in the nursery bed and later transplanted after three to four weeks to rows 60-75cm apart and 45-60cm within the rows. Wider spacing (75x60cm) is usually adopted for late-matur- ing cultivars and closer spacing (60x 45cm) for ear- ly-maturing cultivars.

Seedlings should be grown in a well-aerated medi- um, which has good water holding capacity and at a pH of around 6.5. Generally, peat, bark and vermicu- lite mixes are used. Media problems typicallyinclude excessive tannins and low air filled porosity, which results in poor drainage and the buildup of green mould. The medium should be pre-enriched and the seedlings should be fertilized. Foroptimum germina- tion, the seedling trays should be placed in a germi- nation chamber, at 20 °C with high relative humidity. The seedlings should be moved to the tunnel at the first sign of germination.The ideal temperature for seedling cultivation is 20 °C.

Seedling management is a critical factor in cauli- flower production, as the following factors related to Seedling production may result in physiological disorders Kwita ku ngemwe ni ingenzi mu buhinzi bwa shufureri, kuko ibi bikurikira bifitanye isano no gutubura ingemwe bishobora gutera ibibazo mu mi- kurire:

»   Incorrect sowing time.

»   Cold temperatures, particularly below 7 °C.

»   Cold grown seedlings.

»   Over-fertilization of seedlings.

»   Oversized seedlings at transplant.

»   Temperature differences between the seedling nursery and the farm.

 

A precision seeder is recommended to place single seedlings at a uniform depth.

Field selection, preparation and layout

Good  soil  preparation  is  important  when  planting cauliflower. The best way to determine your soil con- ditions are to have a soil test performed. Cauliflower requires a fertile, well-drained soil with a good water- holding capacity and a pH range of 6 to 7. Working the soil to break up any hardpan, and incorporating manure or compost to a depth of 15 to 20 cm are nor- mally best recommended. If soil must be treated for root-knot nematode, this must be done after the soil is prepared, and allowed an interval of 2 to 3 weeks after treatment before planting.

Cauliflower seedlings ingemwe za Shufureri Source isoko https://plantinstructions.com/

3.Crop management

Manure and fertilizers

Recommendations for supplemental organic matter, fertilizer, lime or manure should be based on a soil test and a Nutrient management plan.

Cauliflower does well when manure is applied, howev- er it is best not to use manure from animals that have been fed turnips or rutabagas. Excessive use of manure may contribute to tip burn, hollow stem, internal brown- ing, head rot and other problems. Uncomposted manure may not be applied directly to the crop prior planting. Lime should be applied to maintain the soil pH in the range of 6.5 to 7.0, unless club root control is required (pH of 7.2). If soil pH is below 6.2, apply lime either in the fall of previous year or six weeks before planting.

Weeding and mulching

Integrated weed management should be practiced prior to planting cauliflower. Management steps include crop rotation, field selection and weed removal before weeds produce  seed  and  preplant  irrigation  to  stimulate  weed emergence so that these seedlings can be killed off with herbicides,  propane  flaming  or  shallow  tillage.  In  addi- tion, careful preparation and spacing of beds and precise planting  make  close  cultivation  more  effective.  Weed control  is  most  critical  for  the  first  30  days  following transplanting until the crop begins to close the leaf cano- py and shade out weeds. Preplant or post-plant herbicides are available for use on cauliflower. Surface spray banding of liquid fertilizer may have the added benefit of burning small weed seedlings as well as fertilizing the crop. Given the planting configuration, effective weed control can be achieved with cultivation. The first cultivation removes weeds from the entire bed except for a band of 10 cm wide around the seedlings. The second cultivation carried out just before the canopy closes throws dirt at the base of the plant, which smothers small weeds. After this cultivation, the canopy shades newly emerged weed seedlings. Hand weeding may be necessary to remove weeds between the plants in the seed-line.

Irrigation

Cauliflower requires adequate soil moisture to maximize yield and quality. It is irrigated most frequently with fur- row and overhead sprinklers. Most growers use sprinkler irrigation to establish transplants and  either  continue  with sprinklers or switch to furrow or drip irrigation for  the remainder of the crop. After transplants are estab- lished, sprinkler irrigations are usually applied at weekly intervals during the spring and summer. A small part of  the hectare can be grown under surface drip irrigation. Some drip irrigated fields are planted on beds of 2 m wide with three lines of plants per bed and two  lines of drip  tape between the plant rows. Using drip irrigation can provide improved access to fields during harvest, espe- cially on heavy soils with limited draina

 

Pest and diseases control

a)           Pests in Cauliflower

 

Pest	Damage	Management
Cabbage Maggot (Delia redicum)     Source: gardeningknowhow.com	lay elliptical white eggs on the stems of crops or in nearby crevices in the soil.   Enter the roots and feed by rasping the plant tissue with a pair of hook like mouthparts and tunneling into the roots.   Causes roots to be misshapen and allows the entry of decay organisms Results in stunted plants.	Cultural controls include covering young plants with floating row cover to prevent the flies from depositing eggs after plant emergence.   Intercropping clovers or other legumes to prevent the flies from find- ing open ground near a brassica stem. -If using chemical controls, scout plants frequently and treat when damage is first observed.
Cutworms (Agrotis ipsilon)     Source: plantvillage.psu.edu	Greyish, fleshy caterpillars up to 5 cm long, which curl up when dis- turbed.   Plants may be chewed off above or below ground level and may be damaged higher up by climbing cutworms.   Most of the cutworm damage is to newly set plants in the field, but they are often found attacking seedlings in plant bed and greenhouses.   Late infestation of variegated cut- worm occasionally occurs.	Prepare the soil two weeks before planting to cultivate in cover crops and destroy weeds.   Check plants frequently and treat when damage is first observed.
Aphid (Brevicoryne brassicae) Source: gardenerspath.com	Aphids are small, soft bodied, slow moving insects.   Aphids feed on heads, flower stalks as well as leaves, resulting in unmar- ketable produce. Aphids feed by piercing plants and sucking out plant sap, resulting in distorted plant parts and a slowing of plant growth.	- Cultural controls include using high pressure sprinkler irrigation to knock the insects off of plants, as well as using living mulch such as clover inter-planted with the cauliflower.

Thrips (Thrips tabaci)   Source:shutterstock.com	They feed by puncturing the leaves and sucking up the exuding sap.   This causes the appearance of dark warts or blisters on the leaves.   They also feed on curds, damaging them and making them unmarketable.	Destroy refuse and control weeds.   Heavy migrations of thrips can oc- cur following the cutting of forage, particularly alfalfa or clover.   It is critical to control them at early head formation (7.5 cm leaf ball).
Flea beetles (Phyllotreta spp.)	small shiny black beetles, about 2 mm in length.   Very active early in the growing season, especially during periods of dry sunny weather.   Damages seedlings and transplants, and to a lesser extent larger plants, by chewing small pinholes through the leaves. There is one generation per year. The larvae live in the soil and feed on roots.	- Biological control options for flea beetle include using a braconid wasp that will parasitize and kill adult flea beetles, and using nematodes that attack the larvae.
Diseases in Cauliflower
Disease	Symptom	Management
Clubroot (Plasmodiophora brassicae Wor.)   Source: researchgate.net	Soil borne disease which affects cauli- flower.   Early infections are difficult to detect as symptoms begin underground.   Symptoms include small to large swellings and other malformations of the roots.	Isolate (if possible) or avoid the use of infested fields.   Do not apply clubroot-infested manure on land to be used to grow brassicas.   Crop rotation Guhinduranya imyaka. Apply lime to raise the pH of the soil to at least 7.2.
Rhizoctonia     Source: agric.wa.gov.au	Soil borne fungi cause two diseases of cauliflower including Damping –off and Wirestem.   Seeds are attacked and decay. Imbuto zirafatwa zikabora.   When plants germinate, but fail to emerge.	Use only sterilized soil or soil that has not previously had brassicas.   Seeds should be hot water treated and also treated with a suitable fungicide.

Disease	Symptom	Management
Grey Leaf Spot and Black Leaf Spot Alternaria brassicae (grey leaf spot)     Source: Infonet-biviosion.org	Causes small and light brown or grey lesions   These diseases are seed and soil borne.   Small black spots (1 to 2 mm in diame- ter) appear on leaves, later turning into a tan colour with target-like concentric rings.   When the spots dry out, the tissue falls from leaves.   -Small brown sunken lesions and decay of cauliflower curds, under very wet conditions.	Use clean, certified seed or a hot water seed.   Practice long rotations between Cole crops.   void overhead irrigation and make sure to incorporate plant debris.   -Good air circulation is needed in the field, as well as in storage.
Downey Mildew (Peronospora parasitica) Source: growveg.com	The plant shows white, fuzzy masses in patches on the underside of leaves, stems and heads.   The tops of leaves turn purple, then later turn yellow or brown.   It may cause browning and black streaking on stems below the curd and black, brown or grey spotting on curds of cauliflower.	Good air and water drainage is critical in controlling this disease, along with avoiding water on the crop in the after- noon and evenings.   Crop rotation with non-brassica plants and incorporating plant debris will also aid in controlling this disease.
Black Rot (anthomonas campestris)   Source: growveg.com	Can live in the soil for one year with- out another Cole crop present.   Humid, rainy conditions favour the disease, which is usually spread by splashing rain or irrigation water.   Black rot lesions first appear at mar- gins of leaves.   Tissue turns yellow and the lesion progresses toward the center of the leaf, usually v-shaped.	Use clean, pathogen-free seed.   Use a 2-year rotation out of crucifers in production fields.   Use a 3-year rotation in the transplant bed.   Contaminated seed can be cleaned by hot water seed treatment of 122°F for 30 min.   Control cruciferous weeds and insect pests.
Blackleg (Phoma lingam.)   Source: farmersweekly.co.za	Can be seed borne. Early signs of blackleg appear as small spots on leaves.   On stems the spots are more linear and often surrounded by purplish borders.   Stem lesions at the soil line usually extend to the root system causing dark cankers.   Fibrous root system may be destroyed. Many plants wilt abruptly and die.	Use clean, certified seed, or seed, which has been hot water, treated.   Practice a 4-year crop rotation, destroy brassica weeds and thoroughly incorporate plant debris.   Avoiding water on the crop in the after- noon and evenings.

 

Harvesting, post-harvesthandling and storage of Cauliflower.

Cauliflowers should be harvested just as the leaves covering the curd begin to spread apart. Since curds

can readily develop a yellow color if they are exposed to the sun, growers in some areas protect the curds by breaking leaves over them or by tying the leaves together. Yellowing reduces the quality of the curd for the fresh market and causes a high percentage of rejection in processing.

Harvesting in one pick is desirable for processing as this keeps harvesting costs to a minimum. For fresh market, usually one or two picks are carried out. This depends on the cultivar. For some cultivars, all curds mature together while for others maturity may be spread over ten to twenty days.

Cauliflowers are marketed either in bulk bins or in packed into cartons of ten (“a dec”). The heads in each carton should all be of similar quality and size. Curds destined for export are trimmed of all leaves prior to packing. Yield will depend on plant numbers and head size. Quality is maintained for a longer period fol- lowing harvest, if the curds are rapidly cooled and then stored under high humidity at zero degrees. Refrig- erated vehicles should be used for transporting cauliflowers to market.

Marketing

 

»   Trim any foliage that overruns the curd of harvested cauliflower.

»   Check for suitable size, uniform shape and healthy color in each selection.

»   Transfer the sorted harvest immediately afterward to the packing area.

»   Pack cauliflower in at least three ways

1. In cartons that carry about nine properly-trimmed heads.
2. 12 heads per carton. For this choice, leave much of the foliage untrimmed over the heads.
3. 15 heads with minor trimming.

»   Keep the fresh cauliflower whether packed or not at 0 degrees Celsius.

»   During packing, maintain this routine by pre-cooling the boxes at zero degrees level.

»   Place ice on each packed crate to allow 99% freshness index of the vegetable upon arrival.

 

References

https://www.selinawamucii.com/produce/fruits-and-vegetables/rwanda-cauliflower/

https://bonnieplants.com/how-to-grow/growing-cauliflower/

https://foodforward.org/2014/04/produce-of-the-month-cauliflower/

https://www.hort.vt.edu/Welbaum/seedproduction/cauliflower.html

https://www.yara.in/crop-nutrition/cauliflower/nutrient-deficiencies---cauliflower/

https://www.gardeningknowhow.com/edible/vegetables/cauliflower/planting-cauliflower-seeds.htm

https://www.indiamart.com/proddetail/cauliflower-seeds-16136636273.html

https://plantinstructions.com/

https://princedebritagne-pro.com https://farmersweekly.co.za