Seed Saving for the Cucurbitaceae Family

This family in its many and varied forms, has been feeding the world since the beginning of recorded history, possibly in every country of the world, in every culture both past and present.

Genus

Species

Common Name

Benincasa

hispida

wax gourd (winter melon)

Citrullus

vulgaris

watermelon, citron

Cucumis

melo

muskmelon, cantaloupe, honeydew, casaba, Armenian cucumber (snake melon), Asian pickling melon, pocket melon (vine pomegranate), vine peach (mango melon), rockmelon

Cucumis

metuliferus

jelly melon (African horned cucumber)

Cucumis

sativus

cucumbers (except Armenian cucumber & African horned cucumber)

Cucurbita

ficifolia

Malabar gourd (chilacayote)

Cucurbita

maxima

squash (vars – banana, buttercup, hubbard, turban, triamble, green chestnut, red kuri, crown)

Cucurbita

mixta

squash (vars – green striped cushaw, white cushaw, wild seroria squashes, silver seeded gourds)

Cucurbita

moschata

squash (vars – butternut, cupola, Chuck’s winter)

Cucurbita

pepo

squash (vars – acorn, crook neck, scallopini, small striped and warted gourds, spaghetti, zucchini, Kamokamo, gem squash)

Lagenaria

siceraria

Hard shelled gourd

Sechium

edule

chayote (choko or vegetable pear)

Pollination: All members rely on insects for pollination, especially bees which will travel several kilometres. All members of the curcurbitaceae family will accept pollen from all other members of the same species. The pumpkins of progeny of uncontrolled crosses will bear little or no resemblance to those of the parents. Luckily there are several species and it’s possible to grow one pumpkin from each species and get a reasonable range without them crossing (i.e. you can grow 4 pumpkins each year, one from each of the pepo, moschata, maxima and mixta families, without them crossing). Traditionally the seed is always saved from pumpkins which set after the first few on each vine. The first few courgettes or the first pumpkins on a vine contain far less seed than those that set later.

Hand Pollination: If you’re saving seed, you can also hand pollinate pumpkins in 5 easy steps:

  1. Go out into your pumpkin patch in the late afternoon and look around for male and female flowers that will open in the morning for the first time. It is pretty easy to tell which ones are about to open, but if you are not confident then I suggest you mark those you guess will open in the morning when the sun comes out and then go out again in the morning to see if you were right; it won’t take long to get that right. Once you know what the flowers look like that will open in the morning, choose 2 male flowers for each female flower you wish to pollinate in the morning (it is easy to see which are female flowers because they all have very visible pumpkins behind the flower, whereas the males don’t). Use cellotape to tape up the flowers so the bees don’t get there before you in the morning, then mark each flower with a bamboo stake or similar so that you can easily and quickly find your flowers in the morning.

  2.  Go out in the morning with more cellotape and a fine paint brush.Firstly pick the male flowers by their stems, and carefully tear off all the petals so that you have only the stamen remaining that you can hold by the flower stem. Lay your stamens on a plate or container then find your female flower and gently peel off the celloptape so that the petals slowly open out exposing the stigma, on top of the style that the pollen travels down to fertilise the ovary in the pumpkin.
    If you are gentle you can simply hold the male stamen by the stem and gently tap pollen from it into and onto the female stigma, or you can use your brush to take pollen from the male to the female. Do this again with your other male flower.

  3. Once you have put your pollen onto the stamen, tape the flowers (petals) back up again so that no bees can gain entry to this flower whilst it is still in a receptive period (which is 1 day, usually only the morning).

  4. Place a tag or label or mark this pumpkin in some way so you know that it has been hand pollinated.

  5. Make sure you water your plants to increase your chances of pollination.

Isolation Distances: If you want to save your own seed, you’ll have to check out any neighbour’s gardens within bee flying distance as well. Each plant produces both male and female flowers. My experience shows that bees as well as wind, use valley systems to travel down, and I have found that sometimes different members of the same species can be grown relatively close without crossing when using these patterns. You will have to do your own research in your own environment!

Minimum Numbers: It is best to grow 6 plants of each cultivar to maintain genetic variability, rather than saving seed from only one fruit or vine.

When To Plant: For the best results you must plant your seed in late September/October, possibly early November to give the plants maximum time to mature.

Rogueing: Choose your best plants if you have many planted, select for health, vigour, taste. If you are concerned that some of your original seed may be crossed then rogueing before the flowers open is critical if you don’t plan on hand pollinating. You can actually see what the fruit is going to be like quite well before the flowers open. If you can see they are not true to type, pull the whole plant out now before the flowers open and the pollen from this plant ruins all the other seed.

Processing: Once you have your pumpkins and melons harvested, it is best to save them to fully mature for up to a month before taking out the seed. Pumpkins will be best to leave for a month, obviously melons a shorter time, and other things like cucumbers somewhere in between. Use common sense here. Traditionally, the seed for saving was taken from the best pumpkin/melon (maybe the best tasting or longest storing etc.) and it was selected from the middle of the cavity.

Fermentation: Rather than simply just collecting and drying the seed, you can put the seed into water for a day or two (stirring often) and then rub and float off all the orange flesh, gelatinous coating and rubbish that hangs on to the seed if simply dried. There is no real need to do this for home seed saving, but it does make for beautiful seed, and free flow seed if you are planning to packet it to share or sell.

Drying: You can then simply dry the seed until it snaps when bent and store (a window sill, dehydrator or greenhouse are good places to dry the seeds). Be sure you have a dehydrator that has a temperature control on it, so that you don’t cook the seed; never dry seeds over 35°C. Pumpkin seed goes mouldy very quicky if not dried well.

Seed Life Expectancy: Watermelon seed will remain viable for 6 years under cool, dry, dark conditions, rockmelons 5 years, cucumber 10 years, all squash and pumpkin 6 years.