Basil Loves Warm Weather
Growing basil / how to guide is primarily focused on high altitude gardening in the Park City Utah area. Basil loves warm weather, lots of sun and plenty of moisture. High summer temperature are responsible for basil going to seed. You will have to wait to plant basil until mid June at high altitude but the higher elevations can be advantageous in preventing your basil going to seed. Basil prefers nutrient-rich and well-drained soils. Before planting, amend soil with compost and fertilizer. Plant after the last frost. Plant the seeds 1/8 inch deep and thin to 3 to 4 inches apart after emergence. The plants germinate in 5-14 days. Irrigate basil with about 1.5 inches of water per week. To maintain rapid leaf growth, side dress with liquid fertilizer every 14 days. When the plants have 6 to 8 leaves, harvesting can begin; remove enough of the stem so that only 2 to 4 leaves remain.
Does pinching off the flowers make more leaves grow? Pinching off the flowers as the form does not stimulate new foliage; in fact it encourages flowers to form in the axils of the leaves thus reducing the yield of the plant. Planting basil every other week and avoid stressing the plants will help keep them from flowering too quickly.
Growing Basil / How To Guide
Soils
Basil prefers fertile, well-drained loamy soils rich in organic matter. It is recommended to amend the soil with compost to be sure that the soil has enough organic matter in it. Choose a site that has good air circulation around the plants.
Soil Preparation
Before planting, add 4-6 inches of compost or 1-2 inches of manure and a complete, all purpose fertilizer (16-16-8). Work compost and fertilizer into the top 6-8 inches of soil.
Plants
Basil can be grown from seed or transplants. Plant seeds or transplants after the last frost of the season. Basil seeds germinate best when soil temperatures are 65-86 degrees F and take about 5 to 14 days to sprout. Transplants take 4 to 6 weeks to grow to size and should be planted after frosts in mid June in high elevations such as Park City Utah.
Planting and Spacing
Sow seeds 1/8 inch deep, cover lightly with soil, and water regularly so that the soil doesn't dry out. Basil grown in full sun has more of the essential oils associated with flavor than shade grown basil. After the seedlings emerge, thin the plants to 3 to 4 inches apart leaving larger ones. Continue to thin the seedlings until the final plant stand is 12 inches apart. Thinned plants can be eaten or transplanted to adjacent areas. High summer temperature and other stresses are responsible for basil going to seed, developing off flavors or stopping leaf production.
Water
Water basil regularly supplying 1.5 inches of water per week to maintain vigorous growth. Water requirements depend on soil type and temperatures. Irrigation will prevent wilting that slows growth, damages roots, and stunts plnats. Drip irrigation systems can work well for watering basil plants.
Fertilization
Basil requires some additional nitrogen to sustain rapid leaf growth, especially when pinching it back to constantly produce more leaves. Once the plants reach the harvestable stage, side dress with organic or all-purpose liquid nitrogen fertilizer sources every 2 to 3 weeks.