"Many catalogues, notably Burpee's, offer these ridiculous devices designed for the gardener too stupid to sow seed by himself - and of course charge extra for them; and to put it plainly, they are a swindle. Anyone who can't scrape a shallow trench with a hoe, then walk down it scattering seed from a packet, had better abandon gardening forthwith. Seed tapes are clumsy affairs that have to be unwound and maneuvered into position, then covered with soil exactly as naked seed is. But they don't germinate any better than seed does - rather worse, the difference being that when sees is sown by hand, the inevitable blank spots can be filled with seeds kept in reserve in the packet. When four out of ten seeds embedded in a tape fail to come up, there is nothing to do about it."
-Eleanor Perenyi Green Thoughts - A Writer in the Garden (1981) p. 207
You know, I've never used seed tape, but I did try a little experiment with paper towels and carrot seeds. See, I'd been having trouble with my carrots. The first 3 sowings resulted in very spotty germination. I now know that this was probably due to the fact that I didn't keep the soil moist enough. But, since I didn't know much about carrots back then, I went looking for a solution. And where do we all go searching for solutions? That's right! The internet. That's when I heard about the "paper towel trick". And I thought this would be my answer. So, I placed the seeds 1" apart between 2 paper towels on a tray and moistened this carrot seed sandwich. Then I waited a few days. The idea was to encourage the seeds to sprout on the paper towels. After seeing what I thought looked like sprout-ation, the little guys got a 1/4" blanket of nice potting soil out in the sunny vegetable bed. Making sure to keep the soil moist this time, I watched carefully as only 1 little carrot seed sprouted. What a let down!
After "The Great Carrot Seed Sandwich Experiment" went bust, I simply planted the seeds without any fanfare, watered them lightly almost everyday, and most of them sprouted. Brilliant.
Any evidence of a successful carrot seed sandwich out there?