Question: Does it matter which way up cucurbit* seeds are sown?
Answer: Have a look at the above photo and guess what my conclusion might be. Some references say sow them on their side - which is the way I usually do - others are non-committal.
I couldn't find any reason why they should be sown on their side, so I decided to conduct a quick trial. Luckily my seed stash had some packets to spare, yielding 44 cucumber, 24 squash and 8 courgette seeds, 76 all told.
I sowed the seeds in four different ways: sideways, flat, upright ("pointy" side of the seed uppermost) and upside down ("pointy" side of the seed downwards). All were sown into labelled cell trays with the same compost and amount of water, then left on a bright, south facing windowsill and emergence days recorded. If there were seeds left to emerge, it was assumed they weren't going to if nothing further was recorded after 5 days.
NB I conducted this trial last summer, when temperatures were warm enough for these seeds to germinate.
* = cucumber, courgette, pumpkin and squash
All seed emergence took place within 5-18 days after they were sown, with 65 seeds (86%) making their appearance.
Sideways sown emerged day 5 to 16
Flat emerged day 6 to 17
Upright emerged day 5 to 18
Downward emerged day 6 to 15
All courgette seeds, 41 out of 44 cucumbers (91%) and 16 out of 24 (67%) squash emerged. See the table below for emergence rates for each seed type by position sown.
|Total emerged/ total sown||41/44||16/24||8/8||65/76 (86%)|
Whilst some variation in emergence times and rates were observed, they weren't significant or consistent enough to conclude that a particular sowing position had an advantage. Emergence rates were good for all positions.
Larger sample sizes are needed for the squash and courgette seeds for firmer conclusions to be drawn for these individual cucurbit types. Pumpkin seeds could also be added to the trial and my usual comments apply about the need to repeat the trial to see if consistent results are obtained.
From now on I won't quite be as careful with which way I sow my seeds as I have done previously. I will be sowing in pots at home as usual, so I have strong plants to withstand the ravages of the allotment slugs when I plant them out at the beginning of June.