Growing seed for harvest 1: Introduction & Lettuce

Organic NZ Magazine: July/August 2005
Section: Farming and Horticulture
Author: Annie Wilson and Colin Walker

In the first of a new series, Colin Walker of the Koanga Institute talks to Annie Wilson about saving heritage seed.

Koanga has received such a multitude of New Zealand’s heritage seeds over the last twenty years from gardeners around the country, that it now requires considerable resources to keep them alive. The scale of the collection is huge and maintaining the viability of all the cultivars requires growing out a certain number of lines to a certain scale, every year.

Growing seed for such a wide range of plants is a highly complex process and requires much initial planning. It also requires considerable expertise, in knowing the optimal planting times, soil types and nutrient needed, in addition to basic knowledge of how to save each seed correctly, then clean and store it. Some plants, of course, are easier to save for seed than others.

Koanga has a three part strategy to keep the seeds alive. The first part of the strategy to keep the seeds alive is to return some of them to the commercial marketplace, so 100 of the most popular varieties have made available to the home gardener, on stands in nurseries and organic shops, and Koanga’s organic seedlings have been selling well in the Auckland area since last spring, and will be available again this spring.

The second part of the strategy involves the growing out of the 500 other lines that need to be maintained. The difficult ones are to be grown by Koanga in Kaiwaka and the Hauraki Region and we are appealing for help in this area.

The third part of the strategy is to encourage the home gardener to plant the easy-to-grow varieties, and start saving seed from them.

In this column we offer information on growing out seed for the home gardener, with a view to getting our valuable heritage vegetable and flower lines back into the nation’s gardens, and keeping them strong there. The self-pollinating species are the easiest, and the cross-pollinated ones more difficult, eg., corn and brassicas.

See the accompanying chart to identify which crops are best for you to grow over the coming months. A certain number of plants need to be grown for collecting seed from, to maintain that species’ genetic strength over time. It is not sufficient to take seed from one plant, but preferably from many, then mix the seed for replanting.

All heritage seed is open pollinated by definition – no hybridisation has occurred, so the seed will grow true to its parent each year, unlike the F1 hybrids that supply most commercially grown vegetables.

We will address nine family groups, each of which have their own needs – some perennial, some biennial, some annual, some self pollinating, some needing cross pollination either through wind action or insects.

We have divided the country into three climatic zones and have allowed for the seasonal variation within each zone. Zone 1 is the South Island from Kaikoura south. Zone 2 is from Kaikoura north to Taupo. Zone 3 is from Taupo north. An example is lettuce, which should go into the ground as a seedling in early September in Zone 3, mid-Sept. in Zone 2 and early October for Zone 1. in order for seed to be collected from it during the optimal Nov-Feb period, which is usually reasonably hot and dry, and produces the best seed collecting and growing conditions. Broad bean seed should also be planted in August for harvesting in the same period.

In coming issues we will write about the right crop for planting at the time of year, with time to germinate before the plants should be in the ground.


Growing lettuce for seed – Latuca Sativa (from Italian sativo, meaning cultivated)

Belongs to the Asteraceae family (including Jerusalem artichoke, sunflower, salsify, scorzonera, endive and yacon). Is self pollinating, ie., the flowers have both female and male parts, so crossing rarely occurs between varieties, but to be completely sure of this it is better to plant another crop between rows of different varieties. Bees and wind cannot affect the pollination process of these plants because pollination has already occurred before the flower even opens. It is the most advanced form of pollination, guaranteeing that the plant stays the same.

Aim for a 300mm spacing between plants when growing for seed, and prepare for a plant that will grow to 600mm and maybe much higher. Remember that early bolting is not desirable, so remove those plants quickly. Choose plants with good characteristics – size, uniformity of shape, disease resistance, tolerance of local weather conditions, and if possible, taste and texture.

Lettuce flowers open over a period of a month or more and the seed, which is feathery in appearance on the branches of the seed stalk, will appear about 12 days after the flowers. Holding a container like a shallow bowl or paper bag under the flower spike, shake the plant any time you see seed maturing.

During rain these seeds can be washed off the plant, so protecting with a plastic bag tied onto the stem is beneficial, or harvesting before the rain arrives.

Alternatively, if it remains dry, you can wait until the branches are all heavily feathered, and then cut them off and bring into a warm, dry environment. Laying the branches on newspaper, for instance, in a glasshouse is satisfactory. Later, shake seed out and after removing unwanted debris, store in a labelled envelope, with the date of harvest and variety written clearly. Airtight jars or ice cream containers can hold the envelopes in a cool dark place.

Koanga holds Tree Lettuce seed which can be picked one leaf at a time up a stalk which keeps getting taller. Winter Lettuce has a long curly leaf, and grows through the cold months.

Finger Leaf has a small pale green leaf and has been grown in Keri Keri since WW2. Stevens Lettuce came from Percy Stevens’ family. Mr Stevens was a professor at Lincoln and brought the seed from Europe after the war. It’s a small lettuce with thick dark green leaves.

Odell’s is a Koanga favourite with crunchy sweet ribs and the best flavour of all. Mignonette has crinkly leaves of a yellow to light green, with red outer leaves, and is slow to bolt. Joe’s is a good sized bunching lettuce that stands well over winter.

Also available as a mixed selection is seed from the Abundant Life Collection in the US. It comes from the states of Oregon and Washington which have a similar climate to New Zealand.

Lettuce varieties differ in terms of ideal climate zones, so it is wise to save seed from a variety best suited to your area.

Next issue we will discuss the main summer crop varieties that are self pollinating, including tomatoes and some bean varieties.