Common problems when farming spinach

A vegetable farmer picks spinach for customers. For optimum production, spinach requires regular water supply throughout the entire growing season as it is shallow-rooted. PHOTO/NMG

What you need to know:

  • Spinach requires proper nutrition for growth, since it is a heavy feeder, to offer a good harvest. Fertiliser application depends on the soil nutritional status. Watering should be adequately done throughout the growing season. Spacing varies depending on the variety, soil nutritional status, and the irrigation method.

Spinach is a common vegetable crop that easily grows in a wide range of ecological zones.
It fetches high prices in the market and is rich in iron and calcium, among other nutrients. However, growing the crop comes with several challenges that make farmers harvest losses.

This helps to keep the soil moist and to suppress weeds. Decomposed mulch releases nutrients into the soil, which are absorbed by the crop. It also helps prevent soil erosion.

Watering should be done regularly because spinach requires high levels of moisture.

Spinach requires sufficient nutrients for proper growth and development. It is, therefore, important to ensure that these nutrients are made available and in the needed quantities. For instance; for basal fertilisers such as DAP, put a table spoon per hole and mix with soil at transplanting.
For CAN, put a tea spoonful and is banded around the plant as top-dressing at three weeks after transplant. NPK, are also be applied after the third harvesting to generate more leaves.

Crop rotation
Spinach should not be planted on the same plot over and over, because this causes pests and diseases to build up in the soil. Rotations should be done with other crops like beans, peas, lettuce, tomatoes and potatoes.

Pests and control
Cutworms and wireworms: Cutworms cut off the stems of young seedlings at ground level while wireworms feed on the foliage and roots. Drench soil with pesticides such as pentagon 50ml/20l, profile 440ec 60ml/20I or any other alternative pesticide available in agrovet shops.

These are small soft bodied insects found on the underside of leaves and/or stems of plant; usually green or yellow in colour. Infestation causes yellowing and distortion of leaves, formation of necrotic spots and stunted shoots. Aphids secrete a sticky, sugary substance (honeydew) which encourages the growth of sooty mold on the plants. Spray pesticides such as kingcode elite 50ec 10ml/20l or lexus 247sc 8ml/20l or loyalty 700wdg 5g/20l or available alternative.

Spinach crown mite 
These mites live deep in the crown of the spinach plant. Their feeding causes deformation of leaves and small holes form in newly expanding leaves. Damage can be to newly emerged seedlings or to older plants. Spray pesticides such as alonze 50ec 5ml/20l or bazooka 18ec 10ml/20l or available alternative.

Slugs and snails 
They leave relatively large holes in spinach leaves. Slimy trails are evident. Drench soil with profile 440ec 6oml/20l.

Leaf miners
These leave meandering tan trails or mines on the leaves as they feed. Heavily infested leaves curl and become distorted. Spray escort 19ec 10ml/20l or any available pesticide recommended by agro vet.

Flea beetles 
These feed mostly on young foliage and the damage consists of a number of small holes, leaving the leaf looking as though it had been hit by a blast. The leaves sometimes have bleached and pitted areas. Spray lexus 247sc 8ml/20l or kingcode elite 50ec 10ml/20l or presento 200sp 5g/20l

Cabbage loopers 
These caterpillars are pale green with white lines running down either side of their body. 
Feeding leads to formation of large or small holes on leaves and the damage is often extensive. Spray kingcode elite 50ec 10ml/20l or baciguard 16wdg or lexus 247sc 8ml/20l.

Feeding causes singular, or closely grouped circular to irregularly shaped holes on foliage. 
Heavy feeding by young larvae leads to skeletonised leaves, and egg clusters may be present on the leaves, which are covered in a whitish scale giving them a cottony or fuzzy appearance. Spray kingcode elite 50ec 10ml/20l or lexus 247sc 8ml/20l or pentagon 50ec 10ml/20l or baciguard 16wdg 15g/20l

Damping off and root rot: Symptoms consist of poor seed germination, pre-emergence death of seedlings, post-emergence death of newly emerged seedlings, stunted plants, yellowed lower leaves, general poor growth, wilting, and eventual collapse and death of older plants. Roots of the infected plants appear water-soaked or brown to black in colour. 
The upper taproot may be girdled by a necrotic lesion, and the tip of the taproot may be necrotic. In severe cases of infection, nearly all roots become girdled or rot off.
While all stages of spinach can be infected by root rot organisms, newly emerging plants and young seedlings are very susceptible. Seek advice from agrovet for effective fungicide fungal diseases.

Leaf spot 
Infection leads to development of small dark spots on the leaves. These enlarge forming brown lesions, which become brittle and eventually crack at the centre. The lesions can also develop on petioles and stems. Spray chariot 500s 20ml/20l or ransom 600wp 15g/20l or bradley 500sc 10ml/20l, however you will be advised on best alternative available

Downy mildew 
Initially dull to bright yellow spots form on cotyledons and leaves of all stages. These spots enlarge and become browning and dry. 
Close inspection of the underside of the leaf often reveals the purple growth of the fungus. 
In severe cases of infection, leaves appear curled and distorted and may take on a blighted effect as a result of numerous infection sites.
Remember, every environment has specific challenges that require extra attention.