Prep the soil.
Whether you're growing herbs in a planter on your windowsill or outdoors, Vierra recommends using a well-mixed combination of peat moss, compost and dirt. "It should be loose enough for water to drain and for the plant's roots to grow and pull nutrients from the soil," he says.
Plant seeds no deeper than half an inch.
The finer the seeds, the shallower they should lie in the soil. Pack them too far into the earth and the weak sprouts won't have enough energy to break through to the surface. Plus, the warmer soil near the top helps spur growth. (Just make sure your plants get six to eight hours of sunlight daily.)
Herbs will rot and die in soggy dirt, says Vierra, as the swampy conditions overwhelm the roots. To check if you're over- or underwatering, grab a tiny chunk of soil just beneath the top layer and squeeze it in your hand. If it starts to crumble, water more often. If it feels mushy, you're overdoing it. If the soil forms a nice ball of dirt, you've got it just right.
Keep 'em contained.
In Oprah's garden, oregano and mint grow so fast, they threaten to suffocate other plants if they aren't pruned regularly. "Their stems just take off and spread like crazy," Vierra says. But with proper trimming, most herbs will cohabit well and grow quickly—expect to see fully mature leaves within just 60 days.
More on Gardening