In USDA ZONE 4A finally thawing out, and I plan to grow some amaranth this summer for grain/lettuce, so I was wondering if it would be acceptable to plant amaranth directly onto the soil right now (where waist-height grass grows), and let it germinate, or should I probably grow it the traditional way of planting it on top of soil, then water it.
We have a huge field next to where I want to spread the seed, so if it becomes invasive we wouldn't care.
We have redroot pigweed in our area, which is a wild amaranth (though other weeds have the name, too). Grass keeps it from sprouting. I've never seen it in a lawn without dead patches of grass (and rarely then, either). So, I'd go for planting it in soil without grass already in it. It grows easily (when it's warm enough; many other weeds sprout in cooler temperatures) and competes for space as well as weeds like lambsquarter, prickly lettuce and mallow. I imagine at least many of the domesticated amaranths are at least somewhat similar, from what I read about them.
If the grass hasn't sprouted yet, it's possible it may be able to grow there, as long as it sprouts first, but I'd still recommend the no-grass route.
Grass can keep a lot of things from sprouting, I've found.
You'll probably want to seed amaranth when it's warm enough to transplant watermelons (not directly after the last frost, but when it gets somewhat warmer), if the domestic kinds are like ours.
I suggest checking with your local extension office to find out if it is acceptable because some species of Amaranth (aka pigweed) may be considered invasive weeds where you are. Some states prohibit the propagation of invasive species. Also an invasive plants may alter the ecosystem in a detrimental manner (e.g. outcompeting a native plants which other species depend on).
Otherwise your amaranth seeds will just need to compete with the existing species in the lawn for space, nutrients, light, and water. If the grass is already established and waist-high, amaranth growing conditions will be a lot less favorable than sowing seeds according to the package's recommendation.
