May is the month for assembling your herbs. The weather is warm enough, finally, to please heat seekers, such as basil and lemongrass, and to coax mint into life for Kentucky Derby juleps.
And if I haven’t quite conveyed how easy, inexpensive and foolproof it is to grow herbs in pots, and how badly I want you to do this, let me just say: GROW HERBS IN POTS.
Here’s how to do it:
The larger the container, the better. A greater volume of soil moderates root temperatures, retains moisture and allows room for crowded herbs to grow. A 14-inch-diameter pot is ideal for housing four to six herbs, don’t go with anything smaller. Forms, colors and materials vary widely.
If you are on a budget, a simple plastic or basic clay pot costing a few dollars will work. If you have deeper pockets and want to make more of a design statement, you can find glazed ceramic pots for about $30 to $60, smart terra cotta pots from $40 to $100, and high-design concrete or resin pots for as much as $200 or more. Metal containers can look stylish, but they get uncomfortably hot in a Washington summer, as can black or dark-hued pottery.
All pots must drain freely, so make sure they have at least one drainage hole. Decorative “feet” — three to a pot — are cheap and can make a vital difference in preventing waterlogged roots, especially if the pot sits directly on concrete or stone paving.
A grouping of pots can provide a focal point and expand your range of herbs, but avoid lots of little pots. Three beefy pots of different diameters and heights can look great, define a corner of a patio, or visually lighten corners and walls.
No potted plant will thrive in poor, dense soil. Don’t use garden soil or stuff left over from last year’s pots. The classic general purpose potting soil is a peat-based mixture with perlite and limestone, often with compost and vermiculite added. You can make your own or buy bags that are ready-made. For herbs, particularly Mediterranean herbs such as rosemary and lavender, some gardeners like to add some gravel or chicken grit to the mix to aid drainage. Adding sand might not help so much.
In creating any effective container garden, the pros give plants three distinct roles: as an upright accent, as a lower-growing mound and as a trailing plant. They are known in the trade as “thrillers, fillers and spillers.” The same principle applies to potted herb gardens.
We asked Adam Pyle, horticulturist at the U.S. Botanic Garden, for some of his favorite herb combinations: