Garden Q&A: How to grow fresh herbs and manage ants in the house

Q: I love cooking with herbs, so it would be handy to have my own supply right outside of the kitchen. Which herbs are the easiest to grow? Any that are really difficult?

A: Yesterday was Herb Day (the first Saturday in May), but nearly every day can be herb day when you have fresh supplies at the ready. In order to grow the widest variety of herbs, all you need is a full sun exposure and excellent drainage in your garden soil or potting mix. A few will make do with less sun (aim for a minimum of three to four hours of direct light), though your harvest will be reduced. I’ve grown parsley, thyme, basil, oregano and tarragon in a balcony planter box receiving only about four hours of late afternoon sun in the summer. They’re not producing abundant growth, but it’s enough to season dinner recipes now and then.

The most cold-hardy, longer-lived candidates include mint, thyme, chives, tarragon and oregano. Short-lived candidates include basil, coriander and dill. Two of the most popular perennial shrub-like herbs – yet the most fickle about drainage – are lavender and rosemary. Some cultivars of rosemary are more cold-tolerant than others, though to have the best success with overwintering them, try to insulate their roots by growing them in the ground; container soil is more vulnerable to drastic temperature swings.

Some herbs you can start from seed while others are best grown from transplants. Nurseries stock-up on herbs prior to our frost-free date, so acclimate any you purchase before mid-May gradually to chilly outdoor temperatures, as even the hardy types are greenhouse-grown at this age.

Grow herbs in soil that isn’t too nutrient-rich, which might dilute their flavor or encourage diseases due to overly-abundant growth. Be aware that mint is a rampant spreader and may need its own container to keep it from overrunning a mixed planting. Fennel can self-sow with abandon if you let it go to seed, and while the original plant won’t be long-lived, its children can keep colonizing the garden for years to come (to the point of being a weed).

In general, herbs don’t have many debilitating pests or diseases, but basil is an exception of note – Basil Downy Mildew can ruin a harvest (though infected leaves are safe to eat), so choose cultivars with noted disease resistance.

You can learn more about the general care of herbs, find harvesting and preserving tips, and troubleshoot herb problems in our collection of herb web pages.

Q: It’s springtime again, so that means it’s time for ants in the house. Do you have tips for discouraging them?

A: Several species of ants can forage in (or nest in ) homes, though occasionally they’ll enter homes if outdoor conditions are stressing the colony (such as over-saturated soil in a poorly-drained nest site). As with most indoor insect pests, the simplest method to keep them out is to deny them access by sealing all gaps and cracks (including repairing torn window screens and worn weather-stripping), and to discourage foraging by keeping areas clean where food is stored, prepared, and eaten.

Ants are pretty small, of course, so I acknowledge it can be hard to exclude them completely. Try to follow their foraging trails to see where they are entering your house, if they seem to be nesting outside. If you suspect they’re nesting inside, try using bait. Keep in mind that bait attractiveness to the ants can vary as they seek different types of food (sugars vs. proteins vs. fats), so you may need to try a different formulation if the first doesn’t work.

A persistent colony nesting inside the home that isn’t sufficiently treated with baits should be assessed by a pest control professional. Some ant species nest in wood that was previously damaged by water while others might nest in a wall void amid the insulation or in the space between floors, so finding the exact site of a nest can be difficult. In these instances, spot-treatment with an appropriately-labeled insecticide by a pest control professional may be warranted.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Extension” to send questions and photos.