Purple Basil
Ocimum basilicum
Purple basil is a purple-leaved form of sweet basil that is grown from seed in full sun and warmth. It is a tender annual that suits containers and is listed as non-toxic to cats and dogs.
Quick facts
- Germination time
- 5–7 days
- Germination temperature
- 18–21 °C64–70 °F
- Sowing depth
- 6 mm¼ in
- Spacing between plants
- 30 cm12 in
- Days to maturity
- Not yet verified
- Sun
- Full sun
Non-toxic to cats and dogs
By SeedBattle EditorsUpdated
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01 · Overview
About purple basil
Purple basil is a sweet basil (Ocimum basilicum) with purple foliage, grown mainly for its ornamental leaves and its use in cooking. Several purple-leaf basil varieties exist, and their foliage can be used decoratively in the garden as well as for garnishes. Basil is a tender annual, aromatic plant with a spicy odor and flavor. Some sources call basil a short-lived perennial, but it is usually grown as an annual.
Growing details
- Start indoors
- 4–5 weeks before the last frost
- Sow outdoors
- At the last frost
- Water
- Not yet verified
- Containers
- Yes
- Height
- 30–46 cm12–18 in
- Spread
- 30–61 cm1–2 ft
- Frost tolerance
- Tender (no frost)
- Soil pH
- Not yet verified
- Life cycle
- Annual
Sowing timeline
When to sow purple basil seeds
Counted from your area's average last spring frost date. Find yours from a local weather service or garden center, then count back or forward.
- Germination time
- 5–7 days
- Germination temperature
- 18–21 °C64–70 °F
- Frost tolerance
- Tender (no frost)
02 · How to grow
How to grow purple basil from seed
Start seeds indoors about 4 or 5 weeks before the last frost date, or sow outdoors after all danger of frost has passed. Sow the seed ¼ inch (6 mm) deep; one guide says ⅛ inch (3 mm) deep. Seeds usually sprout in about 5 to 7 days, and germinate best at 65 to 70 °F (18 to 21 °C). Thin seedlings to about 12 inches (30 cm) apart. Give the plant full sun, with at least 6 hours of direct sun a day. Plants grow to about 12 to 18 inches (30 to 46 cm) tall and can be grown in containers.
03 · Care
Caring for purple basil
Pinch out growing tips to encourage branching and leafy growth. Pinch off flower buds as soon as they form, because flowers reduce leaf flavor. Keep the soil moist and well drained. Avoid heavy nitrogen fertilizer, since too much nitrogen affects the flavor.
At a glance
How purple basil compares with other herbs
Worked out from the growing facts of the 30 seeds in Herbs on SeedBattle.
- Purple Basil
- Each of the other herbs
- Their average
- Germination timeSprouts sooner than average
5–7 days
Average for herbs: 12 days, from 20 other seeds
- Germination temperatureAbout average
18–21 °C64–70 °F
Average for herbs: 19 °C66 °F, from 14 other seeds
- Sowing depthAbout average
6 mm¼ in
Average for herbs: 6 mm¼ in, from 16 other seeds
- Spacing between plantsCloser than average
30 cm12 in
Average for herbs: 34 cm14 in, from 13 other seeds
- HeightShorter than average
30–46 cm12–18 in
Average for herbs: 70 cm2½ ft, from 27 other seeds
04 · Problems
Common purple basil problems
Downy mildew is the main disease to watch for; it causes yellowing between the veins and gray fuzzy growth under the leaves. Plant resistant cultivars such as ‘Obsession’, ‘Devotion’, ‘Prospera’, and ‘Amazel’ to help prevent it. Purple leaf varieties have shown lower rates of downy mildew infection. Aphids and Japanese beetles are occasional pests, and slugs and snails can chew holes in leaves.
05 · Harvest
Harvesting purple basil
Begin harvesting when the plant has 6 to 8 leaves, and cut the stem so that 2 to 4 leaves remain. Harvest before the flowers open, since the flavor fades once the plant flowers.
06 · Storage
Storing purple basil
For short-term storage, place cut stems in a jar of water at room temperature, away from direct sunlight. Don’t store basil in the refrigerator for long, as it discolors the leaves. To freeze, chop the leaves and freeze them in ice cube trays. Don’t oven-dry basil, because the leaves scorch.
07 · Safety
Purple Basil safety
Purple basil is listed as non-toxic to cats and dogs.
Purple Basil questions
How long do purple basil seeds take to germinate?
Seeds usually sprout in about 5 to 7 days when the soil is warm. Another seed company lists 5 to 10 days at 65 to 70 °F (18 to 21 °C).
Can I grow purple basil in a pot?
Yes, purple basil can be grown in containers, both outdoors and indoors under lights. Purple cultivars are also described as well suited to containers.
When should I plant purple basil outdoors?
Sow outdoors after all danger of frost has passed. Basil does not tolerate cold and is readily damaged by frost.
Is purple basil safe for cats and dogs?
Basil is listed as non-toxic to both cats and dogs.
Quick answers
More purple basil questions
Short answers taken from the growing facts on this page.
How deep should I sow purple basil seeds?
Sow them 6 mm¼ in deep.
How far apart should I plant purple basil?
Space the plants 30 cm12 in apart.
How much sun does purple basil need?
Purple basil grows in full sun.
What temperature do purple basil seeds need to sprout?
Purple basil seeds germinate at 18–21 °C64–70 °F.
How tall does purple basil grow?
Purple basil grows 30–46 cm12–18 in tall.
Can purple basil survive frost?
No. Purple basil is tender, so it can't take frost.
Side by side
Compare purple basil with…
Two seeds, every growing fact lined up, so you can pick the one that suits your space.
Herbs
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