Basil Plant: How to Grow Basil From Seed, Pinch and Harvest

Start basil seed indoors 6 to 8 weeks ahead of planting out, or sow outdoors after danger of frost has passed, since basil is a tender annual. Cover seed with about 1/4 inch of soil, then thin to 6 to 12 inches apart in a spot with 6 to 8 or more hours of sun, per University of Minnesota Extension.

The basil plant (Ocimum basilicum) is a warm-weather herb in the mint family, and cold is what sets it back. Frost kills it outright, and chilly nights stall it well before that: Clemson Cooperative Extension keeps transplants indoors until nights stay above 50 F. At four NOAA weather stations, the normal low reaches 50 F 17 to 25 days after the median last spring frost (our count).

Basil at a glance

Sun	At least 6 to 8 hours of bright light (U. of Minnesota); 6 or more hours of direct summer sun (U. of Maryland)
Sowing depth	1/4 inch (U. of Minnesota, Clemson, Johnny's); 1/8 inch (Utah State)
Germination	About 5 to 7 days (U. of Minnesota, Illinois); 5 to 10 days, held at 70 F (Clemson)
Start indoors	Typically 4 to 6 weeks before planting out (Clemson); 6 to 8 weeks (U. of Minnesota)
Plant out	After frost, once nights stay above 50 F and days reach the 70s (Clemson); nights above 55 F (UF/IFAS); soil 60 F or warmer (Illinois)
Spacing	6 to 12 inches (U. of Minnesota); 12 inches (U. of Maryland, Utah State)
First harvest	About 6 weeks after planting (U. of Maryland)
Cold	Tender annual, killed by frost (U. of Minnesota, Clemson); leaves can blacken at 50 F (Illinois) or below 40 F (UF/IFAS)
Soil pH	6.0 to 7.5 (U. of Minnesota); 6.0 to 6.5 (Clemson)

When to plant basil: warm soil and nights above 50 F

Plant basil outside only after your last spring frost, and for transplants wait a little longer, until nights hold above 50 F. Every source here agrees on the frost; they differ on how much warmth to wait for after it:

• After frost danger: Minnesota and Maryland sow seed only after frost danger has passed. Utah State sows seed after the last frost too, and sets transplants out in mid to late May, once its frosts are over.
• Warm soil: Illinois sets transplants out well after the frost-free date, in soil of 60 F or more.
• Warm nights: Clemson waits until the "daytime temperature is consistently in the 70s" and nights stay above 50 F. UF/IFAS, writing for Florida, waits for nights above 55 F.

The reason for the wait is damage, not just slow growth. Illinois says cold soil and cold air can stunt basil and that 50 F can blacken its leaves; UF/IFAS puts the point where many varieties' leaves turn black and fall at below 40 F. If a late frost is forecast after planting, Clemson covers plants for the night with pine straw or an upturned pot or bucket.

The table turns the frost rule and Clemson's warm-night rule into dates at four NOAA weather stations.

Basil planting dates at four NOAA stations (2027 calendar)

Weather station	Last spring 32 F (median)	Sow indoors, typically 4 to 6 weeks before warm nights (Clemson)	Plant out: normal low reaches 50 F (our reading of Clemson)	Normal low drops below 50 F	First fall 32 F (median)
Minneapolis-St. Paul, MN	Apr 23	Apr 4 to Apr 18	May 16	Sep 26	Oct 18
Baltimore (BWI), MD	Apr 10	Mar 24 to Apr 7	May 5	Oct 8	Oct 31
Raleigh-Durham, NC	Mar 31	Mar 8 to Mar 22	Apr 19	Oct 17	Nov 4
Dallas-Fort Worth, TX	Mar 8	Feb 11 to Feb 25	Mar 25	Nov 5	Nov 24

Freeze dates: NOAA 1991-2020 annual normals, 32 F, 50 percent probability column. Warm-night dates: NOAA's 1991-2020 daily normals, the first spring day the normal minimum reaches 50 F and the first fall day it is under 50 F. A normal is an average, so a colder night can still follow. Indoor sowing is our count back of 6 to 4 weeks from the warm-night date, using Clemson's 4 to 6 weeks; Minnesota's 6 to 8 weeks would start each window two weeks earlier. Minnesota and Maryland sow seed only after frost danger has passed; in our reading that is later than the median date in the freeze column, when a frost is still as likely as not.

A USDA zone describes winter lows, not planting dates, so use the station nearest you. Basil will not live through a northern winter outdoors (Minnesota), so take a last big harvest or pot up a plant before the first fall frost (Clemson). In our reading, the under-50 F column marks when the cold damage Illinois describes becomes likely.

How to start basil from seed indoors

Sow basil 1/4 inch deep, somewhere warm (about 70 F), a month or two before your plant-out date. The sources agree on the depth and the warmth but not on how far ahead to sow:

• Minnesota: 6 to 8 weeks ahead, which helps most with slow sprouters such as 'Purple Ruffles'.
• Johnny's Selected Seeds: 6 weeks ahead.
• Clemson: typically 4 to 6 weeks ahead.
• Utah State: transplants need 4 to 6 weeks to reach size.
• Illinois: 3 to 4 weeks is enough for a usable transplant.

Temperature is the part to get right. Illinois wants the mix at 70 degrees or warmer for both germination and early growth. Johnny's gives 5 to 10 days to sprout at 65 to 70 F, and Clemson gives the same 5 to 10 days, with the mix at 70 F. Utah State gives 75 to 85 F soil as ideal for sprouting, which then takes about 10 to 14 days.

1. Fill a cell tray with moist seed-starting mix and sow the seed 1/4 inch deep (Clemson, Johnny's). Holy basil is the exception: Johnny's says it needs some light to germinate, so cover it more thinly.
2. Keep the tray near 70 F until the seedlings are up. In a cool room, a heat mat under the tray is one way to hold that.
3. Once seedlings carry 2 sets of true leaves, move each into its own small pot so it grows on faster (Clemson).
4. Plant out when seedlings have 3 to 4 sets of leaves (Johnny's) and the warm-night date in the table has arrived.

Planting basil outside: spacing and sun

Give basil the sunniest spot you have and well-drained, fertile soil. Minnesota asks for 6 to 8 hours of bright light a day and Maryland for 6 or more hours of direct summer sun. Clemson says basil prefers full sun but does reasonably well with six hours. In hot Florida summers, UF/IFAS likes a little afternoon shade. Utah State adds that sun-grown basil carries more essential oil and better flavor than basil grown in shade.

Spacing. Plant size varies a great deal by variety (NC State lists plants from 4 inches to 3 feet tall), so the sources space differently:

• Minnesota thins or transplants to 6 to 12 inches once seedlings have 2 to 3 pairs of true leaves.
• Maryland spaces plants 12 inches apart in rows 18 inches apart.
• Utah State thins first to 3 to 4 inches, then to a final 12 inches.
• UF/IFAS thins seedlings to about 10 inches.
• Johnny's grows 4 to 8 inches apart in rows 18 inches apart, and says thinning is optional.
• Clemson gives the big 'Genovese' 2 feet, since it can reach 3 to 4 feet tall.

Soil and feeding. Minnesota's pH range is 6.0 to 7.5; Clemson aims for 6.0 to 6.5. Work in compost before planting (Utah State, Clemson), but go easy on fertilizer: Maryland and Clemson both say heavy feeding and fast, lush growth can cost flavor, while Illinois notes that basil in thin, poor soil grows slowly and tastes weak too.

Watering basil

Basil wants steady moisture. Johnny's says it does not tolerate drought and that heat stress can damage it. Minnesota waters deeply every 7 to 10 days, depending on rain; Utah State supplies about 1 1/2 inches of water a week. Mulch holds moisture and keeps weeds down: 2 to 3 inches by Minnesota's figure, 3 inches by Clemson's. Water at the base of the plant, by drip, soaker hose or hand, and keep the leaves dry, which Clemson says makes them less prone to disease.

What to plant with basil

Tomatoes are the pairing with the most study behind it, in our reading. Penn State Extension says interplanted basil helps hide tomatoes from thrips and that ringing tomatoes with basil reduces how many eggs tomato hornworm moths lay; Minnesota points to a few studies of basil against thrips. West Virginia University spaces the basil roughly 10 inches from each tomato plant. Oregon State cautions that strong-scented herbs as pest deterrents still lack enough research. Minnesota also gives basil as an early crop in a bed that peppers or tomatoes move into later. See our companion planting chart.

One caution from Clemson: basil also gets bacterial wilt, so do not plant it where tomatoes died of that disease. If you let a few plants bloom, Penn State says the flowers draw sweat bees, native bees that go on to pollinate nearby crops.

How to pinch basil so it stays bushy

Pinch out the tip of each stem as the plant grows, and pinch off flower buds as soon as they form, as Illinois Extension advises. Taking the tips makes the plant branch into a rounded, leafy bush; leaving flower buds on changes the flavor of the leaves.

NC State pinches back long stem tips, along with any flower buds, for a branching, bushy shape. UF/IFAS says pinching the growing points keeps the plant compact and stretches the harvest season, and Clemson says regular pinching makes thicker plants with more tender leaves.

1. Start while the plant is young: Illinois begins light picking on young plants.
2. Snip or pinch a stem tip off just above a pair of leaves; Minnesota says new growth starts at that point.
3. Repeat on each stem as it lengthens (Maryland), and use what you pinch in the kitchen.
4. From midsummer, look for flower spikes (Clemson) and pinch them out while they are still buds.

Why flowers matter. Minnesota says basil that flowers and sets seed turns woody, makes far fewer leaves and tastes more bitter. UF/IFAS adds that flowering shortens the plant's season. Utah State names what brings flowers on: summer heat and water stress.

Where the sources disagree. Utah State says removing flowers as they appear does not bring on new leaves; it leads the plant to form more flowers where the leaves join the stem. Utah State says sowing basil every other week and avoiding heat and drought stress will help. Clemson lets purple- or pink-flowered types bloom when they are grown partly for show.

How to harvest basil without killing the plant

Harvest basil by snipping young leaves or stem tips whenever you need them, and when you take a whole stem, snip just above a pair of leaves, as Minnesota advises; the plant regrows from there within about a week. Never strip a plant bare: Clemson leaves enough leaves on each plant that its growth does not slow much.

• When to start. Maryland says leaves are ready about 6 weeks after planting. Utah State starts once a plant has 6 to 8 leaves and cuts the stem back so 2 to 4 leaves remain, rotating between plants for a steady supply.
• Time of day. Johnny's picks early in the morning, while it is cool, so the leaves wilt less.
• Weather. Clemson warns against harvesting on rainy days or right after overhead watering: fresh cuts can let in gray mold, and they take about 48 hours to heal.
• A big cut. For one large harvest, Johnny's cuts the whole plant 4 to 6 inches above the ground just before it flowers, which lets it grow back for a second cutting.

Keeping cut basil. Illinois keeps picked stems in water on the counter and says refrigeration discolors the leaves; Johnny's says not to store basil below 50 F. Utah State also stands stems in water, out of direct sun, but for longer storage, 7 to 10 days, it bags the jar and puts it in the refrigerator.

Drying and freezing. Minnesota air-dries small bunches for a week but prefers freezing, since air-dried leaves turn brown. It keeps dried basil about a year and frozen basil up to a year; Utah State uses frozen basil within 3 to 6 months.

Growing basil in pots and on a windowsill

Basil grows well in a pot with drainage holes in the bottom, as long as it gets full sun and steady water; Minnesota notes that pots dry out faster than garden beds. Small types are the easiest fit for pots. Minnesota calls 'Spicy Globe' a good indoor plant because it takes longer than most basils to run to seed; UF/IFAS recommends miniature basils such as 'Dwarf Greek' and 'Spicy Globe' for containers.

Feeding pots. Potted basil needs regular feeding (Utah State), and the sources set different schedules. Minnesota uses liquid fertilizer at half the label strength every 3 to 4 weeks for basil in outdoor containers and every 4 to 6 weeks indoors. Utah State feeds pots weekly.

On a windowsill. Illinois grows basil on a sunny windowsill for fall, winter and early spring: sow a pinch of seed in a small pot of potting mix, keep it moist in full sun, and start picking in about 4 to 5 weeks. A new pot sown every 2 weeks keeps fresh leaves coming.

Through the winter. To carry a garden plant indoors, Clemson cuts it back before the first fall frost, digs up the roots and pots them, and sets the pot in a sunny window. Minnesota warns that winter window light is too weak on its own and that grow lights may need to run 10 to 12 hours a day. Even indoors, basil is an annual and will flower and die in time, so plan on fresh seed each spring (Minnesota).

Downy mildew and other basil problems

Downy mildew is the basil disease to watch for: leaves turn yellow and a gray to purple fuzz forms on their undersides. Cornell's vegetable program ranks it as the most common and the most damaging basil disease in the United States ever since its first report in south Florida in October 2007; Minnesota Extension calls it the most common basil problem there and says it can kill whole plants.

How to tell. The first sign is yellowing that looks like a nutrient shortage (UF/IFAS, Cornell, Clemson), often in patches boxed in by the larger leaf veins. Turn the leaf over: the purplish gray spores grow only on the underside (Cornell). Cornell and UF/IFAS check early in the morning, because the spores form overnight. If a leaf is yellow but clean underneath, both suggest setting it face down on a damp paper towel, sealing it in a plastic bag, leaving it in the dark for a day, then looking again.

How it spreads. The spores ride the wind over long distances, and the pathogen can also arrive on seed (Cornell, Clemson). Warm, wet or humid weather spreads it (Maryland, Clemson).

What helps:

• Resistant varieties. Maryland names 'Obsession', 'Devotion', 'Prospera' and 'Amazel' (sold as plants from cuttings); Clemson names 'Prospera', 'Rutgers Devotion' and 'Rutgers Obsession'. NC State Extension Master Gardener volunteers trialed resistant types against 'Genovese' and named 'Prospera', 'Rutgers Passion' and 'Rutgers Obsession' the top cultivars. Cornell adds a caution: resistance is rarely immunity, a new strain in Israel has overcome the gene in 'Prospera', and a few US growers reported more severe downy mildew on 'Prospera' in 2021 and 2022.
• Other basils. UF/IFAS calls every sweet variety very susceptible, while red types, Thai, lemon, lime and other spicy basils have proved less so. Cornell's evaluations, run before the resistant sweet basils were bred, found the same.
• Sun, air and dry leaves. Plant in full sun with room between plants (Maryland, Clemson), and water with drip or a soaker hose instead of a sprinkler (UF/IFAS, Clemson, Cornell). Cornell notes that home gardeners can bring potted basil indoors to keep it out of the overnight dew.
• Clean up fast. Pull and throw out infected plants promptly (Maryland, Clemson), sow fresh seed in pots or another part of the garden (Maryland), and move the basil bed each year (Clemson).

Other problems Clemson lists. Fusarium wilt is a soil fungus: plants grow normally to 6 to 12 inches, then stunt, brown at the tips and suddenly wilt. It survives in soil for years, so grow a resistant variety such as 'Nufar', 'Aroma 1', 'Aroma 2', 'Newton' or 'Prospera'. Root rots follow soggy soil, so improve drainage and do not overwater (Clemson, Utah State).

Pests. Clemson names Japanese beetles, slugs and aphids as the most common; NC State lists aphids and Japanese beetles, and Utah State adds grasshoppers. Clemson picks Japanese beetles off by hand and drops them into soapy water, and Utah State covers plants with garden fabric against adult beetles.

Basil seeds and supplies

Choose seed by use. 'Genovese' and other sweet basils give the large, sweet green leaves that UF/IFAS points to for pesto. Thai basil brings a licorice-like scent and lemon basil a strong lemon one (Illinois), and both have been less prone to downy mildew than sweet basil (UF/IFAS, Cornell). Where downy mildew turns up every summer, add a resistant variety.

For an indoor start, a cell tray with a clear humidity dome holds the seed, and a heat mat is one way to warm the mix toward the 70 F that Illinois and Clemson give for germination.

What you'll need for basil

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• 

  Sow Right Seeds Genovese Sweet Basil Seed

  'Genovese' and other sweet basils give the large, sweet green leaves that UF/IFAS points to for pesto.

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• 

  Survival Garden Seeds Thai Basil Seeds

  Thai basil brings a licorice-like scent and lemon basil a strong lemon one (Illinois), and both have been less prone to downy mildew than sweet basil (UF/IFAS, Cornell).

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• 

  Seed Needs Spicy Globe Basil Seeds

  Minnesota calls 'Spicy Globe' a good indoor plant; UF/IFAS recommends it for containers.

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• 

  Burpee 72 Cell Greenhouse Kit

  For an indoor start, a cell tray with a clear humidity dome holds the seed.

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• 

  VIVOSUN Seedling Heat Mat, 10 x 20.75 in

  A heat mat is one way to warm the mix toward the 70 F that Illinois and Clemson give for germination.

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Sources we used

Each basil figure on this page traces to a saved copy of one of these pages, which we read in October 2026. Where two of them give different numbers, the page names both.

• "University of Minnesota Extension: Growing basil"
• "University of Illinois Extension: Herb Gardening, Basil"
• "Clemson Cooperative Extension HGIC 1327: Basil"
• "Utah State University Extension: How to Grow Basil in Your Garden"
• "University of Maryland Extension: Growing Basil in the Home Garden" and "Downy Mildew on Basil in the Home Garden"
• "UF/IFAS Gardening Solutions: Basil"
• "NC State Extension Gardener Plant Toolbox: Ocimum basilicum"
• "Cornell Vegetable Program: Basil Downy Mildew"
• "Johnny's Selected Seeds: Basil, Key Growing Information"
• "Penn State Extension: Herbs Make Good Plant Partners and Companions", "University of Minnesota Extension: Companion planting in home gardens", "Oregon State University Extension: Companion Planting" and "West Virginia University Extension: Companion Planting"
• "NOAA NCEI: U.S. Climate Normals, 1991-2020": freeze dates and daily low temperatures at four airports

Related guides

• How to grow tomatoes, basil's usual bed partner.
• How to grow peppers, another warm-weather crop started indoors.
• How to grow cilantro, the cool-season herb for the months basil cannot take.
• Companion planting chart, with the evidence behind basil and tomatoes.
• Nightshades, the tomato and pepper family whose beds basil often shares.
• How to grow cucumbers, which get their own downy mildew, a relative of basil's (Cornell).
• How to grow spinach, which Minnesota names with basil as an early crop for a bed that later takes peppers or tomatoes.
• Grow lights for indoor plants, including shelf lights for basil and other herbs indoors.
• Indoor herb gardens, for basil on a kitchen counter under a built-in light.

Frequently asked questions

When should I plant basil?

Plant basil outdoors after your last spring frost, and set transplants out once nights stay above 50 F, as Clemson advises. Minnesota and Maryland sow seed only after frost danger has passed. At four NOAA stations, the normal low reaches 50 F 17 to 25 days after the median last frost, so check the station nearest you.

How far apart should you plant basil?

Space basil 6 to 12 inches apart, per University of Minnesota Extension, or 12 inches in rows 18 inches apart, as Maryland does. Johnny's Selected Seeds spaces plants closer, at 4 to 8 inches. Large varieties need more room: Clemson gives 'Genovese', which can grow 3 to 4 feet tall, a full 2 feet.

When should you pinch basil?

Pinch the stem tips as the plant grows to keep it bushy, and pinch off flower buds as soon as they form, per University of Illinois Extension. Begin while the plant is young and snip just above a pair of leaves, where new shoots will grow. Clemson says many varieties start making flower spikes by midsummer.

How do you harvest basil so it keeps growing?

Cut each stem just above a pair of leaves, and new growth starts at that cut within about a week, per University of Minnesota Extension. Leave enough leaves on every plant to keep it growing. Utah State starts at 6 to 8 leaves and leaves 2 to 4 behind; Johnny's picks early in the morning, while it is cool.

Can basil grow indoors?

Yes, with plenty of bright light, though in winter you may need grow lights for 10 to 12 hours a day because window light alone falls short, per University of Minnesota Extension. Illinois grows basil in a small pot on a sunny windowsill, picks from about 4 to 5 weeks after sowing, and sows a new pot every 2 weeks.

Can you grow basil in pots?

Yes, in a container with drainage holes in the bottom, per University of Minnesota Extension, which notes that pots dry out faster than beds, so water more often. Compact types such as 'Spicy Globe' and 'Dwarf Greek' fit pots well (UF/IFAS). Minnesota feeds outdoor pots with half-strength liquid fertilizer every 3 to 4 weeks.

Why are my basil leaves turning yellow?

Yellow leaves are the most noticeable sign of basil downy mildew, per University of Maryland Extension, though they can look like a nutrient shortage. Check the undersides early in the morning for gray to purple fuzz (Cornell). If so, pull the plant and next time grow a resistant variety such as 'Prospera' (Clemson), though resistance is rarely immunity (Cornell).

What grows well with basil?

Tomatoes, according to Penn State Extension, which says basil planted among tomatoes helps hide them from thrips and cuts tomato hornworm egg laying. Minnesota points to a few studies on thrips, while Oregon State says scented herb pairings still lack enough research. West Virginia University puts basil roughly 10 inches from each tomato plant.