Plant Profile- Pumpkin

When every crop you grow requires the sweat of your brow to produce rather than relying on machines and inputs to push them along it makes you carefully consider the cost and benefits of the crop and their role in the wider farm system. One factor than becomes really important when you grow on any scale for yourself is ease of storage. Crops that grow a perishable product that needs picking in a narrow time frame and that have few options for preservation or storage will always be very minor seasonal treats. The real backbone of the operation are crops that can either ideally be stored in the ground, or somewhat less ideally stored with fairly simple protection post harvest, and finally the worst option being stored after some elaborate preservation like drying or fermentation. In climates with more dramatic cold or dry seasons storage is more important and also more straightforward. In our humid subtropical climate storage in the ground for many crops becomes more feasible.

This all relates to pumpkins I promise. There are many species of cucurbits that fall under this broad label. The zucchini is a specialised version of Cucurbita pepo, which also includes some marrows and pumpkin like winter squashes that aren’t grown often in Australia, along with forms that produces hullless pepita type seeds. These grow fairly well for me but our local melon fly destroys virtually all of the fruit even if I grow them through winter. Rather than spraying, or netting, or a million other interventions I simply don’t grow this type. The large pumpkins like Queensland blue are in Cucurbita maxima. These perform well sometimes, but if the season is too hot or wet tend to struggle, with the just the occasional good season every few years. They are great though because the fruit have good storage properties, getting by for months on the verandah as long as the rats don’t find them. The better match for our climate is Cucurbita moschata, that includes butternut and jap pumpkins. We have a locally adapted strain of jap pumpkins that is so vigorous it often self sows in the paddocks anywhere the grass gets thin. One monster plant recently grew to about 100 square meters and produced nearly 40 huge fruit, all without any attention on my behalf.

The problem with this variety is the fruit have terrible storage qualities. The skin is thin and easily damaged, causing them to start rotting long before they can be used. The wonder of the huge harvest quickly turns into dread at the chore of picking through the pile for stinking slime bombs before they detonate. After a bit of research I found that there were older varieties of moschata pumpkins that have good storage qualities, and better yet there was a local heritage pumpkin seed producer who stocked a wide range of them. I selected out the most promising varieties and sowed seed in tube pots in late September last year just as a little warmth crept back into the days. Large pumpkin seeds normally make excellent candidates for direct sowing, but the new varieties were in too small quantities to risk them with this method. In addition I had no idea of the seed viability, so I could have prepared a bed, sowed the seed, waited long enough to be sure nothing was coming up and then missed my window of opportunity for the year. Fortunately the seed germinated strongly and was transplanted out then watered by hand a few times to help them establish (something I would never do with direct sowed seed that I had more of to resow later). Despite the area being unimproved soil with compacted thin clay and a light smattering of goose manure, despite a moderate amount of weed competition that was merely slashed back a couple of times, and despite having almost no rain throughout the growing season the pumpkins produced a useful crop for the purposes of variety assessment by January. If I had given every variety everything it needed then I would have no way of knowing which ones could actually handle our conditions.

Of the dozen or so varieties about half failed to either grow or produce fruit. Melon fly was observed destroying fruit of several varieties while others set well and resisted the pest. A few varieties only managed to produce a single fruit that allowed fruit quality to be assessed. One variety called Seminole really stood out with several fruit produced. This strain is named after the native Indian tribe from northern Florida, a bioregion with a very similar climate to our farm. It is also luckily one of the best storage pumpkins around. The fruit harvested in January this year has rolled around the verandah with no special treatment and still looks immaculate in October, even longer than Queensland blue. The cavity is a bit on the big side but the seeds separate cleanly. The shape is fairly smooth so the rind can be easily cut away from the flesh. The seeds are a bit small for my liking. My shocking confession after all this is that pumpkin doesn’t agree with me at all (digestive upset no matter how I prepare it that runs in my family). The roast seeds are the target food for me and as it turns out the ancestors of pumpkins were domesticated first for their oil and protein rich seeds. Only much later did mutations produce the large sweet fruit we know today. In my system I would ideally have a vigorous storage pumpkin with large seed that I can also feed the flesh to my dairy goats.

The next step in the breeding project is to experiment with crossing the storable Seminole with the locally adapted and productive jap strains. I will direct sow both of these out on my creek flats soon once the beds are ready and we get a little rain. I have large amounts of the open pollinated Seminole seed that most likely outcrossed with any of the dozen other diverse heritage strains in the trial. I am also growing out some pure Seminole seedlings again this year in an isolated patch to produce more pure seed.

The final step is to find the best way to grow pumpkins and incorporate them into my wider systems. Pumpkins are field crops that are better grown in more extensive systems with more space and fewer inputs than other vegetables. Strains with strong root systems also benefit from having deeper top soil, so growing on my creek flats is the place to aim for. Previously I tried growing pumpkins and other cucurbits in mounts of goat manure, aiming to replicate their original habit of being dispersed in the droppings of large herbivores. This never worked as well as when they grew themselves in a space with a large mass of decomposing plant matter. Self sown seedlings of our nearly wild jap pumpkins often come up in debris piles and thrive. As such I see pumpkins and their relatives as a good first season crop after a zone is taken out of fallow and large amounts of biomass are on hand to pile up in winter/spring. The vining and climbing growth habits mean they can grow over the top of a weed smothering biomass pile while their roots grow underneath it. I also need to get a better sense of the ideal time to grow both moschata and maxima pumpkins, possibly intersowing them so that no matter what kind of season we have one species will perform well.

All this breeding and experimentation will probably take 5-10 years to reach a point that I am happy with. The notion that someone could simply start growing food tomorrow if the industrial system sputtered out is a dangerous story. Developing locally adapted zero input systems takes time and many errors that you can’t afford if you are relying on the crop to survive. Long ago people would inherit locally adapted varieties from their communities along with the techniques to grow them reliably. Heritage plant strains are mostly degraded and even if they were not, which of the dozens in circulation are adapted for your particular location and what techniques are needed to grow and use them? Australia is at a particular disadvantage compared to most of the world since we don’t even have a pre-industrial farming culture to fall back on since it simply never existed in any meaningful form (the colony was a net food importer for the first century). We have gathered hints of aboriginal agriculture before that but even then the soil, ecosystems, weather and the very air we breathe are all changing rapidly. The pre-industrial past can guide our efforts but ultimately we have to create a new world in our post-industrial future, one new seed at a time.

Seedlings of new pumpkin varieties ready for transplanting.
The saddest pumpkin patch in the world, but a couple of varieties made it through the valley of death.
Self sown wildish jap pumpkin. How the seed survived under a burning pile I have no idea.
Seminole pumpkins opened for inspection, by far the best overall variety for my farm.

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