Skip to main content Skip to navigation
Washington State University

WSU Snohomish County Extension office has moved!

Our office is now located in the Snohomish County Parks & Recreation Administration Office at Willis Tucker Park, 6705 Puget Park Drive, Snohomish, 98296.

Basil Garden

Posted by kate.ryan | August 18, 2014

Basil GardenIf you do any Italian cooking at all, you’ll want to include basil in the herb garden. Basil can’t be planted until after the last frost date, but in the heat of summer it will produce abundantly. Recipes below!


1 or more basil plants or packet(s) of seed
Large planting container, window box, or small garden plot


There are many varieties to choose from, well over 100 at last count. The most common is sweet basil, a plant that can grow to 24 inches during the season. Several different purple basil varieties, while tasting no different, lend a beautiful deep burgundy sparkle to any dish as well as to the garden. Purple basil creates a beautiful color when steeped in white vinegar for a flavored vinegar. Recently rediscovered by many cooks, lemon basil adds a lemon and basil fragrance to both the garden and the kitchen. Thai basil adds a licorice flavor and tastes great in Asian cooking. Holy basil is used frequently in several Indian continent cuisines.


Basil is a heat-loving annual herb that does best in moist, well-drained soil situated in full sun. Whether in a container or garden, plants need good light, soil, adequate space, and water. Choose a location that is somewhat flat and receives a minimum of 8-10 hours of full sunlight each day. More is always better. In addition, make sure you have a good source of water nearby. Western Washington summers are often very dry throughout July & August. Your basil garden will likely need a good watering at least once a week during the growing season and daily watering if in a container.

Soil Prep

If you are starting a new, in-ground garden, it’s a good idea to have the soil tested first. Your local conservation district should be able to help you with that task. You can also use raised beds or large pots/barrels. Fill them with clean soil and/or compost for an instant garden.

Mix 3-4 inches of compost into a new garden to improve its overall soil biology and health. If you already have a garden area, be sure to add 1-2 inches of compost each year to maintain soil health.


To ensure adequate nutrition for your basil garden, add a complete organic fertilizer (available at most garden and nursery centers) to the planting hole for each plant. Mix it in well before planting. Be sure to follow directions for the product you are using; generally use 2-3 tablespoons per basil plant. If planting seed, scratch 1 cup per 10 row feet into the soil underneath where you will plant the seed.


Start seeds indoors six weeks before the last frost date or seed directly in the garden (about 1/4 inch deep) well after the last frost date when soil is warm. In Western Washington, that can often mean not planting till mid-June in a cool year. Set transplants or thin seedlings to stand 8-12 inches apart. For more information on growing basil, this fact sheet can help.

basil flower budMaintenance

When plants reach 4-6 inches in height, pinch off the center shoot to force side growth and prevent early flowering. Any time flower buds start to develop (see picture at right), pinch off all growing tips and use the results for a batch of pesto. Mulch is recommended since basil likes a steady moisture supply. Early cold weather can ruin a maturing crop, so be sure to harvest the entire plant if temperatures are expected to dip much below 50 degrees F.


Basil is at its most pungent when fresh. The best time to harvest is in the morning after the dew dries from the leaves, but before it gets very warm. Look for tips where the plant is just starting to bud, well before flowers bloom. Snip leaves or branches at this time and pinch off flower buds to keep the plant productive. You also can cut the entire plant about 6 to 8 inches above ground, leaving at least one node with two young shoots intact.
The plant should produce a second but smaller harvest several weeks later, especially if you give the plants a good drench of fish fertilizer at a rate of 2 tablespoons to a gallon of water.

Basil Recipes

basil pestoBasil loses much of its flavor when dried, thus freezing is the best method for long-term storage. Add leaves to a blender or food processor and lightly process, adding only enough olive oil to allow the processor to work, spoon results into ice cube trays for freezing. Store frozen cubes in a sealed container and use within 6 months. You can also make and freeze your favorite pesto recipe for later.

Classic Basil Pesto

2 cups packed fresh basil leaves
1/3- 1/2 cup olive oil
1/4 cup pine nuts, blanched almonds, or walnuts
2 garlic cloves, crushed
1/2 cup freshly grated Parmesan cheese

Combine first 4 ingredients in blender. Blend until paste forms, stopping often to push down basil. Add cheese and blend until just mixed. Transfer to small bowl. Can be made 1 day ahead. Top with 1/2 inch olive oil (to prevent the basil from turning black from oxidation) and chill. Can also be frozen.

Basil Vinegar

2 cups or more sweet or purple basil
2 cups +/- white wine vinegar

Lightly crush and loosely pack the basil into a clean glass jar. Pour enough vinegar over the basil until they are completely covered. Tightly cover the jar, label, and date it. Store at room temperature away from direct light or heat for at least 2 weeks.

Use a jelly bag or coffee filter to strain the vinegar into an another clean, glass jar. Discard the spent basil. Cork or tightly cover the bottle, label, and store in a cool, dark place. Best if used within 1 year.