Seed Saving for the Convolvulaceae Family

Pollination: Not applicable for kumara.

Isolation Distances: Not applicable.

Minimum Numbers: 1 plant will be enough, but more would be better, you will notice – many subtle differences between plants and being able to save your seed tubers from a large population will help keep a strong line. Ideally over 100 plants.

When To Plant: Kumara are perennial vines that are propagated vegetatively, either by shoots from the tubers or cuttings from the tips of the growing plants. When placed in a warm, moist, but very free draining medium (in August), shoots form along the sides of each tuber, take root, can then be broken off with their new roots and planted straight into the garden. We plant our kumara in deep boxes with 8cm of compost below them and 8cm above.

Rogueing/Selection: Kumara commonly carry serious viruses, and growers who keep their own seed over the years need to develop a system for minimising this problem. Kumara with very dark patchy skin often have a virus, and it will affect their keeping qualities seriously.
Joseph Land, our kumara curator, minimises the problem by taking cuttings from the first tips that appear from the tubers each Spring (or  alternatively from the plants when they begin running), rooting them in a seed tray and then planting them out in a separate block. The tubers from this block are the ones to save for growing tupu the following Spring. This is the traditional method for keeping kumara healthy. It is well known that the strongest growing tips are the healthiest, and best places to collect virus free material.

Support/Protection: Not applicable.

Harvest: Harvest on a waning moon, keeping the tubers from each plant separate until you can see which plants have the best crops and these will be your seed kumara.

Drying: Dry well on the ground, turning them after 2-3 days of sun and then another day or so for the other side. Cover the kumara at night with the leaves that were cut off them, removing them before the sun comes out each day.

Selection/Storage: Select the big fat female tubers that have narrow ends rather than the long thin kumara with less obvious ends to the kumara for seed. Store the kumara in cardboard or wooden boxes or kete, keeping each kumara from touching another by wrapping in paper, or putting in layers of sawdust, or using layers of silver fern or bracken, which are fungal deterrents.