Basil
Ocimum basilicum
Aromatic herb that thrives in warm conditions alongside tomatoes. Pinch out flower heads regularly to encourage bushy leaf growth.
Overview
Companion Planting
Good Companions
Tomato
Bell Pepper
Chili Pepper
Eggplant
Asparagus
Petunia
GrapeBad Companions
SageToxicity
Listed as non-toxic to dogs, cats, and humans by the ASPCA. Large quantities may cause mild digestive upset in pets; avoid concentrated basil essential oil around cats.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Pinch off flower buds regularly to encourage bushy leaf growth and prevent the plant from going to seed.
Common Pests
Aphids
Symptoms: Clusters of small soft-bodied insects on leaf undersides and stems; curled, sticky, or yellowing leaves.
Treatment: Spray with insecticidal soap or neem oil; dislodge with a strong water jet.
Prevention: Encourage beneficial insects like ladybugs; avoid excessive nitrogen fertilization.
Japanese Beetles
Symptoms: Skeletonized leaves with only veins remaining; shiny metallic-green beetles visible on foliage.
Treatment: Hand-pick beetles in the morning; apply neem oil or pyrethrin-based sprays for heavy infestations.
Prevention: Use row covers during peak beetle season; treat surrounding lawn with milky spore to reduce grub populations.
Whiteflies
Symptoms: Tiny white flying insects on leaf undersides; yellowing leaves, sticky honeydew residue, and sooty mold.
Treatment: Apply insecticidal soap or neem oil to undersides of leaves; use yellow sticky traps.
Prevention: Inspect transplants before planting; maintain good air circulation and avoid over-watering.
Common Diseases
Downy Mildew (Peronospora belbahrii)
Symptoms: Yellowing between leaf veins on upper surface; grey-purple fuzzy sporulation on leaf undersides.
Treatment: Remove and destroy affected leaves immediately; apply copper-based fungicide as a preventive measure.
Prevention: Ensure good air circulation with adequate spacing; water at the base, never overhead; choose resistant varieties.
Fusarium Wilt (Fusarium oxysporum f. sp. basilici)
Symptoms: Yellowing and wilting leaves starting from the crown; brown streaks inside stems; stunted growth and sudden plant death.
Treatment: No cure once infected; remove and destroy affected plants and do not compost them.
Prevention: Use certified disease-free seed and resistant cultivars (e.g., 'Nufar'); rotate crops and sterilize tools between plants.
Gray Mold (Botrytis cinerea)
Symptoms: Water-soaked spots on leaves and stems that develop a fuzzy gray mold; wilting and stem collapse in humid conditions.
Treatment: Prune affected tissue well below the infection; improve ventilation and reduce humidity around plants.
Prevention: Space plants for good airflow; avoid overhead watering; remove plant debris promptly.