Can Gomphrena Seeds Be Sowed Outside?

Timing

• Starting globe amaranth seeds outdoors takes good timing, because sowing too early may cause the seeds to fail, and sowing too late will not give the plants time to mature and bloom before the first autumn frost. As a general rule, wait two to three weeks after the last average spring frost date to sow the seeds outdoors. The soil must be warmed to around 70 degrees Fahrenheit during the day to ensure successful germination, so consult the weather forecast to make sure the weather is compliant before sowing.

Site Preparation

• Globe amaranth performs best in full sun with sandy, fast-draining soil. Two weeks before sowing the seeds, thoroughly weed a suitably sunny garden bed and remove all rocks, sticks, rubbish and other debris from the soil. Turn over the soil and break apart any large clumps, using a shovel or cultivating fork. If the native soil is heavy or clay-based, amend the top 6 to 10 inches with coarse sand. Even out the surface with a rake or hoe to limit the chances of runoff, which can easily wash the seeds away. Weed the bed a second time the day before sowing the globe amaranth seeds to eliminate any emerging weed seedlings.

Sowing

• Although easy to germinate, globe amaranth seeds possess a naturally low viability and must be sown in fairly large amounts to ensure a workable crop of seedlings. For instance, if six plants are desired, sow 12 seeds. The seeds are tiny and tedious to sow individually, so it is best to broadcast the seeds evenly over the prepared bed. Don't worry if the seeds aren't perfectly spaced because they will be thinned out later; just try to avoid drastically uneven seeding. Gently tamp the seeds onto the soil surface, using the flat side of a shovel, and then cover them with a scant layer of soil to limit light exposure, since it decreases germination.

Germination Process

• The key to successfully germinating globe amaranth seeds outdoors is to maintain moderate soil moisture at all times without overwatering the seeds. Test the moisture content in the soil by pressing the surface with the palm of your hand. Water to a 3-inch depth if the soil feels almost dry to the touch. Test the soil twice daily during hot weather, and water accordingly. A misting or spray nozzle is best for watering small, shallowly sown seeds because it creates a gentle, diffuse stream of water that is less likely to dislodge the seeds. Healthy, viable globe amaranth seeds will germinate in two to three weeks.

Aftercare

• True to their reputation as low-maintenance landscape plants, globe amaranth seedlings require relatively little aftercare apart from thinning out and regular irrigation. The mature plants spread to roughly 1 foot, so thin out the seedlings to one every 12 to 18 inches, depending on how densely you wish to grow them. Wait until the seedlings produce a mature pair of leaves, and then remove the least vigorous ones. Water the globe amaranth seedlings every few days, allowing the soil to dry out in the top few inches between waterings. Reduce watering to once a week as they mature.