Although the care of peppermint is a little more involved than just sticking it in the ground, it certainly isn’t intricate. First and foremost, this plant needs lots of water and it is often found naturalized by streams and ponds where the soil is rich and the drainage is good. It won’t tolerate dry conditions. While partial sun is sufficient for peppermint, planting it in full sun will increase the potency of its oils and medicinal qualities.
Though not as invasive as some of its mint relatives, no instructions on how to grow peppermint would be complete without mentioning its tendency to spread. Because of this, many gardeners prefer growing peppermint in containers. Others grow it in the ground with wood or plastic edging buried around the bed to prevent the spread of roots. Whatever method is chosen, good care of peppermint includes moving the plants to a new location every three or four years. They tend to weaken and become spindly if left in the same place for too long.
If you're using seed flats or another method of germination, here's the best approach: set one or two seeds in shallow 1/4-inch holes in moist seed-starting mix. Cover the flat with plastic wrap and germinate at 65 degrees F or above.
If you are starting the seeds in late winter for transplanting in spring, begin about 6 weeks before last scheduled frost. Peppermint will be ready to pick on an as-needed basis about 3 weeks after transplanting; it grows so quickly that you never have to worry about taking too much, as long as you leave a few green leafy stems on the plant! Harvest all summer and fall. Zones 4-9.
73 days from sowing.
How to Sow Peppermint:
Best sown indoors at alternating temperatures of 55 and 72°
Sow with NO cover as light aids in germination
Seeds can also be sown outdoors when the soil is warming in the spring
Sow with barely any cover
Indoors and out, expect germination in 15-30 days
When sowing seed outdoors, we recommend a maximum planting depth of 4X the width of the seed
How to Grow Peppermint: Transplanting: Transplant when there are at least two sets of true leaves Spacing: Space 12 inches apart Lighting: Site in full sun to light shade Soil: Site in a light, rich, moist, but well-drained soil Additional Care: As plants vigorously spread underground via runners, plant them in submerged containers or in areas bordered by walkways or edging. Pinch to encourage branching and sheer plants after flowering to prevent seed formation. For indoor culture, it is best to start new plants from seed rather than potting up clumps from the garden Appearance: This plant grows 3 feet tall and spreads indefinitely.