Is it a British thing or an American import? That’s the first big question about Halloween: The second question is "what’s it got to do with gardeners" beyond growing those enormous pumpkins?
To answer the first question, the Christian festival of All Saints Eve or All Hallows Eve is thought to have absorbed the original Celtic festival of Samhain. This was a celebration of the end of summer, the end of harvest time, and a transition to a different season. It’s the crossing of this threshold between the light and warmth of summer, and the darkness and cold of winter, which the Celts felt left the last night of the year (31st October) neither in this year nor the next, but floating betwixt and between, present in the spirit world. So, Halloween begins as more a British tradition than an American one.
What if anything does this mean for gardeners? Well, the marking of change between one year and the next is a great prompt to avoid future gardening horrors! At Genus we use Halloween as a time to get the garden ready for winter before the worst of the weather arrives. We avoid the potential horrors of pests and disease by finishing the last of the harvesting, clearing and then cleaning out the greenhouse. We avoid the horror of poor soils by getting the leaf mould bins sorted, ready to collect leaves for mould composting. Most importantly, we get out the gardening notebook and reflect on what worked this year, and what can be learnt from the gardening year, and therefore what can be and planned for next. This avoids the horror of serious over-spending on those tempting offers and plants we’ll notice when flicking through seed and plant catalogues over winter.
And finally, Halloween gardening means considering an alternative decorative use for a Scarecrow too!
I’ve just received a reminder about the clocks changing back to GMT. That will be the end of summer then! Not that you would know it. This year the Genus garden is still full of flower even so late in the year. We've beds full of flowering cosmos keeping the sight and feel of summer going very late into the season.
What accounts for this extended flowering period? It’s interesting to know that it’s not just down to temperature. Flowering plants divide up into three groups, short day plants, long day plants and day neutral plants. They might not be reacting to the time shown on our watches, but flowering in short day plants is triggered when there is a longer period of uninterrupted night time darkness. Short day species include ponsettia, Christmas cactus, chrysanthemums. Conversely long day plants see their flowering brought on by short periods of darkness and include plants associated with high summer such as rudbeckia, foxglove, lettuce, spinach, and potatoes. Day neutral plants flower regardless of day length and include tomatoes, petunias, cucumbers, viola, dandelion and sunflowers.
This phenomenon called “photoperiodism” can be manipulated, breeders have worked with plants such as spinach to find varieties that have shorter critical day lengths so that flowering is put off and the harvesting period is extended.
The cosmos doing so well in the Genus garden is obviously a short day plant, so as long as the weather holds out, it will be doing it’s best to flower, on and on and on!