Herbs You Can Start from Seed Now

Hannah O'Connor
Aug 15
6 min read

August offers warm soil and long days, making it ideal for starting certain herbs from seed. Warm-season herbs will germinate quickly and continue to produce until frost, while some cool-season herbs benefit from an early start for robust fall growth. By planting now, you can take advantage of fast germination, healthier root development, and extended harvests.

Starting from seed also gives you access to a broader range of varieties than you’ll find as transplants. With proper care, these herbs can keep your garden productive well into the cooler months!

Warm-Season Herbs to Start in August

These herbs thrive in the heat and are perfectly suited for summer planting. They sprout quickly in warm soil and will keep producing flavorful leaves right up until the first frost.

Basil

Planting: Sow seeds 1/4" deep, 12" apart in full sun and well-drained, fertile soil enriched with compost. Avoid overwatering, which can lead to root rot.
Harvest: Begin picking once plants have 6–8 sets of leaves. Pinch flower buds regularly to prolong the harvest and prevent the leaves from becoming bitter. Succession sow every 3–4 weeks for a steady supply.
Uses: Fresh in salads, pesto, pasta sauces, poultry, and meat dishes; best added at the end of cooking to preserve flavor. Leaves can also be frozen in oil or dried for winter use.
Growth Habit: Tender annual, 20–24" tall, bushy form.
Variety Examples: Genovese, Lemon, Thai, Holy, Cinnamon, Purple.

Borage

Planting: Direct-sow seeds 1/4–1/2" deep, 12" apart in full sun; thrives in average, well-draining soil and tolerates poor fertility.
Harvest: Pick young leaves for the mildest flavor; harvest flowers as they open for use in salads or as a garnish. The plant will self-seed readily if flowers are left to mature.
Uses: Leaves for salads and teas; flowers for garnish, pickles, soups, and stews. Flowers also attract pollinators, which benefits nearby vegetables.
Growth Habit: Annual, 20–24" tall with coarse, hairy leaves and blue flowers.

Chervil

Planting: Sow seeds 1/4" deep, 6" apart in partial shade; prefers moist, well-drained soil rich in organic matter. Avoid transplanting, as roots are delicate.
Harvest: Snip mature leaves as needed, starting from the outside of the plant. Best used fresh, as flavor fades quickly when dried.
Uses: Salads, soups, meat and poultry seasoning, garnishes, and herbal butters; pairs especially well with egg dishes and spring vegetables.
Growth Habit: Annual, about 18" tall; lacy, light green leaves.

Dill

Planting: Sow seeds 1/4" deep, 12" apart in full sun or light shade; prefers loose, well-drained soil. For continuous harvest, sow seeds every 2–3 weeks.
Harvest: Cut seed heads before seeds drop; harvest young leaves for fresh flavor before flowering. Avoid planting near carrots to prevent cross-pollination.
Uses: Seeds for pickling, bread, and sauces; leaves for fish dishes, dips, and salads. Both seeds and leaves can be dried for storage.
Growth Habit: Annual, 24–36" tall with feathery green foliage.
Variety Examples: Bouquet, Mammoth.

Lemongrass

Planting: Sow seeds 1/4" deep, 24" apart in full sun and rich, moist soil. Keep evenly watered during germination and early growth.
Harvest: Cut stalks at the base once they reach finger thickness; outer leaves can be used earlier for teas or broth. Divide clumps every few years to maintain vigor.
Uses: Curries, teas, marinades, soups, and stir-fries; outer leaves can also be used to flavor stocks. Dried stalks retain aroma for months.
Growth Habit: Perennial in Zone 9, forming tall grassy clumps.

Summer Savory

Planting: Sow seeds 1/8" deep, 6–9" apart in full sun and well-drained soil. Benefits from a layer of mulch to retain moisture in summer heat.
Harvest: Gather leaves when flowering begins; dry in bundles hung in an airy, shaded place. Leaves can also be frozen to preserve flavor.
Uses: Seasoning for beans, poultry, meat dishes, dressings, teas, and vinegars; often used as a milder substitute for thyme.
Growth Habit: Annual, about 18" tall with small gray-green leaves.

Cool-Season Herbs to Start in August for Fall Harvest

These herbs can germinate in warm soil but thrive as temperatures begin to cool, allowing them to mature, which extends harvests through fall and winter.

Catnip & Catmint

Planting: Sow seeds 1/8" deep, 12–18" apart in full sun to partial shade. Prefers well-drained soil; drought-tolerant once established.
Harvest: Cut stems when plants begin to flower for the strongest aroma.
Uses: Catnip is popular for cats; both are also ornamental and attract pollinators. Leaves can be used in teas.
Growth Habit: Perennial in Zone 9, 18–36" tall, spreading clumps.

Chives

Planting: Sow seeds 1/4" deep, 4–6" apart in full sun and fertile, well-drained soil. Keep evenly moist until germination.
Harvest: Snip leaves to within 1–2" of the base; frequent harvesting encourages tender regrowth.
Uses: Mild onion flavor for salads, soups, egg dishes, dips, and as a garnish. Flower heads are not only edible but also attractive in the garden.
Growth Habit: Perennial, 12–18" tall in clumps.
Variety Examples: Common Chives, Garlic Chives.

Cilantro

Planting: Sow seeds 1/4" deep, 6–8" apart in full sun to light shade. Prefers fertile, well-drained soil and benefits from consistent moisture during germination.
Harvest: Cut outer leaves when 4–6" tall, allowing the center to keep producing. Succession sow every 2–3 weeks for a steady supply.
Uses: Fresh in salsa, salads, soups, curries, and Mexican, Asian, and Middle Eastern dishes. Seeds (coriander) can be dried and used as a spice.
Growth Habit: Annual, 12–18" tall with bright green, finely divided leaves.
Variety Examples: Long-Standing, Slow-Bolt.

Oregano

Planting: Sow seeds 1/8" deep, 8–10" apart in full sun and well-drained soil. Start in pots or direct-sow where it will grow permanently.
Harvest: Pinch tips regularly to encourage branching; flavor is strongest just before flowering.
Uses: Mediterranean dishes, pizza, pasta sauces, soups, marinades; dries well for storage.
Growth Habit: Perennial in Zone 9, low-growing, 8–12" tall.
Variety Examples: Greek, Italian.

Parsley

Planting: Sow seeds 1/4" deep, 6–8" apart in rich, well-drained soil with full sun to part shade. Germination can be slow (up to 3 weeks); soaking seeds overnight can speed sprouting.
Harvest: Snip outer stems at the base; avoid cutting the center to keep plants productive. It can be harvested year-round in mild winters.
Uses: Fresh in salads, soups, stews, sauces, and as a garnish; also great for drying or freezing in ice cube trays with water or oil.
Growth Habit: Biennial in mild climates, grown as an annual; 12–18" tall.
Variety Examples: Curly, Flat-Leaf (Italian).

Sage

Planting: Sow seeds 1/4" deep, 12–18" apart in full sun and well-drained soil. Start in pots for easier germination.
Harvest: Cut leaves as needed once the plants are well-established; the flavor is strongest before flowering.
Uses: Poultry stuffing, sausage, stews, roasted meats, teas; dries well for long-term storage.
Growth Habit: Perennial in Zone 9, 18–24" tall, woody stems.

Thyme

Planting: Sow seeds 1/8" deep, 6–8" apart in full sun and sandy, well-drained soil. Start indoors or in containers for best establishment.
Harvest: Snip sprigs as needed, avoiding the removal of more than one-third of the plant at a time.
Uses: Poultry, fish, soups, stews, roasted vegetables; holds flavor well when dried.
Growth Habit: Perennial in Zone 9, 6–12" tall, spreading.
Variety Examples: English, Lemon.

Tips for Starting Herbs from Seed

Planting herbs in the heat of August requires a few adjustments to ensure good germination and healthy growth. These tips will help maximize your success in Zone 9.

Prepare the Soil

Enrich planting areas with compost or well-rotted organic matter to improve fertility, moisture retention, and drainage.
Most herbs prefer slightly alkaline to neutral soil (pH 6.0–7.5); a soil test can confirm your pH and nutrient needs.
For containers, use a high-quality potting mix instead of garden soil to minimize compaction and enhance drainage.

Watering Practices

Keep the soil evenly moist during germination; even slight drying can kill seedlings.
Water early in the morning to reduce evaporation and help foliage dry before night, preventing fungal problems.
Avoid overwatering; most herbs dislike having their roots in soggy soil.

Sunlight & Spacing

Most herbs require 6–8 hours of direct sunlight daily; exceptions, such as chervil and cilantro, tolerate partial shade in hot months.
Provide sufficient spacing between plants to allow for adequate airflow and reduce disease risk, following the specific recommendations for each herb.

Fertilizing for Healthy Growth

Start with fertile soil and feed lightly once seedlings have developed two sets of true leaves.
Use an organic, slow-release fertilizer such as MicroLife Ultimate 8-4-6 to encourage steady, balanced growth without excessive leaf softness.

Extend the Harvest

Use succession planting for short-season herbs like dill, cilantro, and basil to maintain a steady supply.
Pinch flower buds before they open to delay bolting and maintain leaf flavor.
For perennials like oregano, thyme, and chives, allow the plants to establish well before heavy harvesting so they return strong the following year.

Conclusion

Starting herbs from seed in August may seem challenging in the Texas heat, but with the right plant choices and care, it can set your garden up for months of fresh, flavorful herbs. Warm-season herbs, such as basil, borage, and dill, take advantage of the heat to germinate quickly and produce until frost, while cool-season favorites like parsley, cilantro, and thyme benefit from the head start and thrive as temperatures cool.

By preparing the soil well, watering consistently, and providing the correct light and spacing, you can enjoy healthy plants and extended harvests. Succession planting and proper harvesting techniques will keep your kitchen stocked with aromatic, flavorful herbs well into the cooler months — and for many perennials, for years to come. August planting is an opportunity to bridge the gap between summer and fall gardening, ensuring your garden remains vibrant, productive, and full of fresh herbs throughout the entire season.

Sources

“Growing Herbs in Texas.” Texas A&M AgriLife Extension, AgriLife Extension, https://agrilifebookstore.org.