Snow pea and Sugar snap pea
Note Number: AG1342
Published: November 2007
Updated: November 2009
Snow pea (Pisum sativum var. macrocarpon), Sugar snaps (Pisum sativum var. saccharatum) and garden pea are members of the Fabaceae (formally Leguminosae) family. Also known as legume family which consists of over seventeen thousand species distributed throughout the temperate, subtropical and tropical zones of the world. The most prominent feature of legume family is the ability of fixing atmospheric nitrogen into a plant useable form with the aid of bacteria living in root nodules.
Peas are low in calories and are good source of fibre, vitamin C, iron, potassium and magnesium.
Compared to the most grown garden pea, snow peas and sugar snaps are sweet, crisp and have less fibre in the pods. Snow Peas have flat pods and are eaten before its seeds are properly formed. Therefore both the pods and seeds can be consumed whole. They may be eaten raw and in salads, lightly boiled, steamed or used in 'stir-fry' and Asian dishes. The shoots from established plants may also be used for Asian cooking and in salads. The pods of sugar snap peas snap like a green bean and have thick walls and are sweet. Unlike the snow pea, the sugar snap pea is picked at a more mature stage and is fully rounded.
There are two types of both snow pea and sugar snap peas; determinate and indeterminate. This describes the growth habit of the plant. Varieties belong to determinate type are shorter and can be grown as a ground crop without trellis.
The tall varieties belong to indeterminate type and are generally poor climbers and need to be supported to be up right. Therefore a selection of a variety mainly depends on the preferred cultivation practices. However, time to maturity, disease resistance and product quality etc. also need to be carefully considered.
The snow pea plant is a vine and grows up to 60 - 200 cm depending on the variety.
The most popular variety in Victoria is Snowman which is also known as Oregon Giant. This has dark green larger pods and has some resistance to powdery mildew and Fusarium wilt.
Several commercial varieties of snow peas have been introduced recently to Australia. They are; Prolific, purple-flowered, tall, vigorous with large pods and high yield; Snowflake , white-flowered, tall, medium to large pods and medium yields; Sweet Pod , white-flowers, tall plant, medium pod size and yield with resistance to powdery mildew; Mammoth Melting Sugar, white flowers, medium size plant, small pods with fair yields.
Sugar snap peas
Snap pea were developed by crossing garden pea with snow pea. Snap peas produce oval to round pods. Most snap pea varieties have strings in the pods, but these peel off easily. The newest varieties have no strings but have smaller pods with low yields.
There are varieties that are resistant to powdery mildew disease. Several varieties of sugar snap peas are now available in Australia and they are either climbing, or dwarf types. Most of these produce reasonable yields with favourable pod qualities. However germination and plant vigour can be poor. Popular varieties in Victoria are Sugar Bon, Sugar Anne and Cascadia.
Peas are thought to have originated in the Mediterranean region. Despite being moderate to low yielders, peas have been continually grown for thousands of years due to their favourable eating qualities and their ability to improve soil.
Snow peas and sugar peas produce best yields and quality in cool and moist growing conditions. The crop is sensitive to heat. Temperatures above 30°C will cause poor pollination, early maturity and lower yields. Ideal growing conditions are an average daily temperatures of 15-18 0C with a maximum of 24 0 C and minimum 7 0C.
Stems and foliage are seldom affected by frost, but damage may occur if a cold snap follows a period of warm weather. Flowers are made sterile by frost and pods can be damaged; affected pods have a white mottled skin. The planting date must be chosen to avoid frost from flowering onwards.
The ideal temperature for germination is 22 0C and germinations time is reduced with lower soil temperatures. At temperatures above 24 0C germination is rapid but seedling losses may be higher due to soil borne diseases.
Peas can be grown on a wide range of soil types, providing the soil is well drained. Good drainage is essential for vigorous growth. Peas, as most legumes, prefer a pH range of 6.0 to 7.0 (water). Lime needs to be added if the soils are too acidic and below pH 5.5 (water). The minimum soil temperature for growth is 10°C.
Although the indeterminate types have a creeping growth habit, they are not strong climbers. Therefore they need to be supported with some form of trellis to manage the vigorous growth and facilitate harvesting, weeding and other cultural practices. The widely adopted system is a two-wire 'tomato' trellis. Trellising is normally constructed using wooden posts fixed in a row at every 6 to 10 m distances. Wires or strings are then run at 20 to 40 cm to support the vines. The direction of planting and trellising may be considered to improve air circulation in the crop to reduce the incidence of mildew.
Peas are sown directly into the soil. About 100 kg of seed is needed for a hectare. Seeds are sown 2 to 3 cm deep in the soil and germinate in 1 ½ weeks. Spacing within the rows should be 7 to 10 cm. The distance between rows of bush varieties should be 60 to 70 cm. For tall varieties on trellis, rows should be 1 to 1.5m apart.
It is recommended that soil analyses be conducted well in advance of planting. This will help to identify the fertilizer requirements for the crop.
Because legumes are capable of fixing atmospheric nitrogen via symbiotic association of soil bacteria it may be expected that peas need little or no supplemental nitrogen. If the paddock is likely to be low in nitrogen there should be a pre-plant application of N at 20kg/ha. The crop however, will fix very little nitrogen unless the seeds are properly inoculated with the appropriate species of Rhizobium bacterium. Inoculation helps if the crop is to be grown in a previously uncropped paddock.
Growers do not generally inoculate seeds in commercial crops in Victoria. If required, inoculum can be bought in powder form and applied to dampened seeds. Mix until the seeds are fully covered and plant as soon as possible.
Phosphorus is an important nutrient for early root development and assists with flowering, fruiting and sugar development. Peas being legumes are efficient at absorbing phosphorus from the soil. However as most Australian soils are deficient in phosphorus, plants have to be fertilised with phosphorus fertilisers. Concentrated super phosphate fertilisers are preferred as they contain less cadmium. Phosphorous should be applied at 40-50 kg/ha pre-planting.
Potassium is essential for plant vigour, growth and resistance against disease. The amount to apply has to be decided after conducting a soil analysis but around 20-30kg/ha may need to be applied pre-planting
Several elements such as magnesium, manganese, boron, iron and copper, zinc and molybdenum are required for healthy growth of snow peas. The requirement of each nutrient depends on the availability of those nutrients in the soil.
Generally a complete fertiliser is used and banded with the seeds at planting. Super phosphate may be applied prior to planting. The rate of the pre-plant fertiliser should be determined based on the results of the soil analysis.
The mixing of compost before planting at up to 50 cubic meters per hectare is beneficial. Compost will supply nutrients and help to retain soil moisture and added nutrients in the soil.
If the soil is low in nitrogen, several weeks after planting at around 10-20 kg/ha of N. If leaves are light green during growth a second application may be needed. The second application should be given no later than 3 weeks before flowering to avoid vigorous vegetative growth. Excessive nitrogen application can result in excessive vegetative growth leading to poor flowering and pod set.
Farmers should be aware of the potential dangers of using phosphatic fertilisers with high levels of cadmium.
If cadmium in a fertiliser is in excess of 1 mg/kg the label or advice note must contain the statement:
"WARNING – this product contains cadmium. Continued use of this product in agricultural situations may lead to residue levels in plant and animal products in excess of the maximum level specified by the Australia New Zealand Food Standards Code and the accumulation of cadmium in soils."
DPI is concerned about long-term accumulation of heavy metals in soils and believes that accurate product information assists primary producers to maintain sustainable agricultural practices. Low concentrations of heavy metals generally occur naturally in soils, however, these concentrations occasionally increase due to exposure to industrial sources or contaminants in fertilisers. Compliance of fertiliser products to regulated standards supports sustainable agricultural systems and helps to reduce the potential for accumulation of heavy metals in soils and plants.
Growers should consult fertiliser suppliers or manufacturers for advice on the cadmium levels of fertilisers they are considered using.
Soil moisture and Irrigation
Peas require a moist soil particularly at flowering and pod development. The majority of Victorian edible peas are cultivated in higher rainfall areas of Southeast Victoria. Irrigation will be required especially in lower rainfall areas to maintain to soil moisture. Crops grown on trellis are well suited to the use of drip irrigation. Moisture monitoring equipment, such as tensiometers should be used to monitor soil moisture levels and schedule irrigation.
Pests and diseases
Snow peas and sugar snap peas are closely related to the garden pea and likely to be attacked by the same pests and diseases. Depending on the season, pests and diseases can cause heavy losses.
The pests most likely to damage pea crops are onion thrips (Thrips tabaci) causing spotting of pods, Heliothis caterpillars which attack leaves and pods, red-legged earth mite (Halotydeus destructor) that attack base of stems and young leaves, two spotted mites (Tetranychus urticae) and aphids (Macrosiphum euphorbiae) which attack leaves and thrips (Frankliniella species) that damage pods.
Roots of pea are damaged by Cutworms (Agrotis spp) and root knot nematodes.
Peas in Southern Australia are affected by several fungal diseases.
Aschocyta - caused by three different fungi, Ascochyta pisi, Phoma medicaginis and Mycosphaerella pinodes which affect leaves, stems and pods with tan colored spots later turning to black.
Foot rot- caused by fungi of Pythium spp and Rhizoctonia.
Downy mildew caused byPeronospora viciae which shows as small yellow blotches on the upper surface of the leaf and grey to purple fungal growth on the underside.
Powdery mildew by Erysiphe pisi, whichappears as discoloured spots on the upper leaf followed by white powdery growth giving the foliage a blue white appearance.
Root rot caused by Fusarium.
The severity of disease symptoms mainly depends on seasonal weather conditions.
Planting resistant varieties and disease free seeds combine with 3-5 year crop rotations will significantly reduce incidence of disease.
Integrated Pest Management (IPM)
Very few chemicals are registered for pests and disease control in edible peas in Victoria.
However chemical use can be drastically reduced if IPM is practised. IPM involves the use of resistant varieties and healthy seeds, crop rotation, frequent crop monitoring, early detection and identification of the pest or disease etc. Recently IPM practices have become popular and growers have observed reduction of production costs and increased market acceptance for their products.
Chemical users must ensure they read and understand all sections of the chemical label prior to use.
Peas are not very sensitive to weed pressure. In fact weeding can do more harm than good as peas have numerous surface roots that are sensitive to disturbance.
The APVMA maintains a database of all chemicals registered for the control of pests (including weeds) in Australia. Refer to the APVMA or your chemical reseller for chemicals registered for the control of pests. Ensure you meet the relevant Maximum Residue Limits (MRLs) for the chemical in the end market, be it domestic or export.
Chemical users must ensure they read and understand all sections of the chemical label prior to use.
Harvesting has to be done at the right time when the pod is around 7.5 to 10 cm long and 2.5 cm wide. The pod is still flat at this stage and the seeds are just starting to swell. At harvest a pod may average 7 grams in weight. Pods of most snow pea varieties are at the right harvesting stage approximately 10 days after flowering and have to be continually harvested at 2 day intervals for best quality. Harvesting commences at 8 to 12 weeks after planting and may continue for 8 to 10 weeks. Pickers can harvest approximately 10-11 kg per hour. This may take longer in wet weather in winter, as the old flowers may stick to the pod. Yields of snow peas range from 2 to 7 t/ha.
Contrastinglysugar snap peas are harvested when the pods are round and up to 7.5 cm long with the seeds almost at full size. These may be harvested for 4 to 6 weeks. A good picking rate is about 20 kg per hour per person.
Pods of snow peas and sugar peas are usually prepacked in 500 g to 2 kg plastic bags. These bags are packed in 10 kg cartons, or polystyrene containers. After they have been pre-cooled to 2°C, they may also be prepacked into polystyrene trays of varying sizes from 175 g to 2 kg and covered with plastic wrapping. Snow peas may be stored at 0 to 2°C with 90 to 95 per cent relative humidity for up to one to two weeks in a high humidity cool room.
For information relating to the safe and appropriate use of chemicals, including management of chemical residues and licensing requirements, contact us and ask to speak to your local chemical standards officer or visit our Chemical use page.
This Agnote was developed by Neville Fernando and Rob Dimsey, Farm Services Victoria, November 2007.
It was reviewed by Neville Fernando, Farm Services Victoria, November 2009.
Published and Authorised by:
Department of Environment and Primary Industries
1 Spring Street
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The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication