It differs. I've done it two ways. Planting right when the seed pops, and the taproot just begins to poke out. And i've also waited, and let the taproot grow about an inch before planting. Either way, I got results.

Although I got them quicker letting it grow an inch.

But it's alot safer (alot safer) to just plant them root down, right when you notice they've popped. Because waiting for them to get an inch long, can risk your roots being drowned. I have yet to have that problem, when waiting for them to grow an inch before planting, but it is def. possible.

The only downside to planting right when you see the seed pop, is that you'll have to wait a bit longer to see results. Usually 2-5 days. Whereas when you let the root grow an inch before planting, you sometimes see results (seedlings) the very next day after planting them. Sometimes even same day!

Still, it's quite risky though. I'd suggest planting after they pop.

And furthermore, not being too impatient with them. They will show up! If you planted them correctly, you will get a seedling! It's hard to screw this part of the process up, lol. The only thing that'll screw it up, is impatience.

Be patient. You'll more than likely see results, within a week.