Basil (Osimum basilicum) is a member of the mint family. There are several types of basil. The most common culinary type is sweet basil. Specialty types include Thai, purple, lemon and small-leaved bush types. Basil seed is not always true to type. Try to obtain high quality seed that is uniform with a high germination percentage.

Varieties

• Sweet/Pesto: Genovese, Italian Large Leaf, Nufar (FR), Aroma 2 (FR)
• Thai: Sweet Thai, Siam Queen, Thai Magic
• Purple: Dark Opal, Purple Ruffles, Osmin Purple, Magical Michael, Red Rubin
• Bush: Spicy Globe, Spicy Bush
• Scented: Sweet Dani (lemon), Lime, Holy (medicinal)

FR = resistant to Fusarium wilt

Spacing and Seeding

Because it is highly sensitive to cold, basil is often started indoors and transplanted after danger of frost. Prior to transplanting, plants should be 6” tall (four to six weeks old) and can be pruned to encourage branching. Basil seeds will germinate within 8 to 14 days at soil temperatures between 65°F and 80°F, with an optimum of 70°F. If field soils are warm enough, basil can be direct-seeded in a well-prepared seedbed at a spacing of eight to 10 seeds per foot and later thinned. Basil is often grown at a spacing of 6” to 12” between plants in double-rows on black plastic mulch on beds 2’ to 4’ wide.

Culture and Harvest

Basil grows well in a warm, well-drained soil with pH 6.0-7.5 and requires adequate soil moisture throughout the growing season. Drip irrigation allows consistent application of water while also reducing foliar diseases. Although adequate fertility is required, excess nitrogen applications can cause post-harvest discoloration and reduce flavor.

Basil is first harvested 60 to 70 days after seeding. Harvests should take place in the morning after the dew has left the plants. Depending on the intended use and market, individual leaves or entire tips of stems may be harvested. Plants may be harvested every one to seven days, depending on the amount removed. Basil can grow up to 1” per day and can be harvested one to five times throughout the season. Plants will set seed if flower spikes are not removed as they appear. Fresh basil is easily damaged by rough handling, dessication and chilling (<40°F). Basil can be cooled by rinsing in cool (55°F) water, but should be dried completely prior to packing.

Cultural management of insects, diseases and weeds are necessary because few insecticides, fungicides and herbicides are registered for use on basil.

Weed Control

Suggestions for weed management in basil include use of the Stale Seedbed Technique and use of plasti-culture. Both glyphosate (Roundup) and pelargonic acid (Scythe) are registered for stale seedbed use. Flaming can also be used. Stale seed beds can be used between plastic mulch (be careful with flaming as it melts the plastic). Basil usually grows quickly and shades the planting hole in plasticulture, out-competing weed growth. Apply the plastic at least two to three weeks prior to planting and kill the weeds between the mulch prior to setting the basil plants on the plastic. On bare ground culture, keep cultivations shallow to protect crop roots. Do not move soil into the crop row as basil plants may be more susceptible to diseases when soil is mounded against the stems of the crop.

Insect Control

NOTE:  For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 20 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

Aphids

For more information on biology, see aphids in the pepper section.

azadirachtin (Neemix 4.5): 5 to 7 oz/A (0 dh, REI 12h, Group 18). Suppression and adult feeding deterrence. OMRI listed.

Beauveria bassiana (Mycotrol O): 8 to 32 oz/A (0 dh, REI 4h, Group 22). Treat when populations are low and thoroughly cover foliage. Takes 7 to 10 days after application to see control. OMRI listed.

imidacloprid (Admire Pro): 7 to 10.5 oz/A (14 dh, REI 12h, Group 4A). May be applied as an in-furrow spray, transplant water drench, during transplanting or through trickle irrigation. See plant-back restrictions.

imidacloprid (Provado 1.6F): 3.5 oz/A (7 dh, REI 12h, Group 4A). For resistance management purposes, do not use a Provado foliar application following another nicotinoid (Group 4A) insecticide application on the same crop. See plant-back restrictions.

insecticidal soap (M-Pede): 1.25 to 2.5 oz/gal water (0 dh, REI 12h). Apply with companion aphicide. OMRI listed.

pyrethrin (PyGanic EC5.0): 4.5 to 18 oz/A (0 dh, REI 12h, Group 3A). OMRI listed.

pyrethrins + piperonyl butoxide (Pyrenone): 1 tsp/gal, or 1 to12 oz/A (0 dh, REI 12h, Group 3A).

Japanese and Oriental Beetles

Beetles migrate from turf or pastures starting in July and skeletonize leaves as they feed. Row covers can prevent feeding. The basil variety Nufar is very attractive to japanese beetles and can be used for a trap crop if sprayed with spinosad or spinetoram (SpinTor, Entrust or Radiant).

pyrethrin (PyGanic EC5.0): 4.5 to 18 oz/A (0 dh, REI 12h, Group 3A). Japanese beetles only. OMRI listed.

pyrethrins + piperonyl butoxide (Pyrenone): 1 tsp/gal, or 1 to 12 oz/A (0 dh, REI 12h, Group 3A).

Leafminers

Leafminers generally are controlled by natural enemies unless disrupted by broad-spectrum insecticide applications. Some species may be transported on transplants from southern or western locations. Control broadleaf weeds in and around the planting. Rotate insecticide groups to sow resistance. Syystemic insecticides may control larae within leaves.

abamectin (Agri-Mek* 0.15 EC): 8 to 16 oz/A (14 dh, REI 12h, Group 6).

azadirachtin (Neemix 4.5): 4 to 7 oz/A (0 dh, REI 12h, Group 18). OMRI listed.

pyrethrins + piperonyl butoxide (Pyrenone): 1 tsp/gal, or 1 to12 oz/A (0 dh, REI 12h, Group 3A).

Disease Control

Purchase disease-free seed. Use resistant varieties where feasible. Promptly remove any stock plants that are diseased or low in vigor. Use separate greenhouses for herb production and keep stock plants separate from production areas. There are few fungicides or bactericides registered for herbs.

NOTE:  For the products for disease control listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 22 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

Bacterial Leaf Spot (Pseudomonas)

Disinfect all benches, equipment, and pots. Purchase culture-indexed plants and disease-free seed. Avoid overhead irrigation. Discard infected plants. Clean production areas thoroughly after harvest as bacteria can survive in dead leaves.

Botrytis blight and stem canker (Botrytis cinera)

Management of environmental conditions such as temperature, relative humidity and duration of leaf wetness is vital to Botrytis control. Control weeds and remove plant debris between crops and during production. Provide good air circulation and reduce humidity within the plant canopy by proper plant spacing, plant height, and fertility. Water in the morning, never late in the day.

cyprodinil plus fludioxonil (Switch 62.5 WG): 11-14 oz/A. (7 dh, REI 12h, Groups 9 & 12).Do not make more than two consecutive applications.

 Damping-off, Crown and Root Rot (Pythium, Rhizoctonia, & Phytophthora)

Use pasteurized soil or soil-less mixes for transplant production. Disinfect all flats, pots, and tools. Use bottom heat to promote rapid seed germination. Avoid over-watering, over-fertilizing, and overcrowding. Promptly rogue out infected plants. Manage fungus gnats and shoreflies. 

Downy Mildew (Peronospora species)

Downy Mildew of basil is rapidly becoming a major production problem. Start with certified, disease-free seed. Promptly remove and destroy infected plants. Reduce leaf wetness periods by plant spacing, improving air circulation, and watering when plants will dry quickly.

potassium bicarbonate (MilStop): 2.0 to 3.0 lb/A. (0 dh, REI 1 h, Group M1).Uniform and complete coverage is essential for effective results. Do not store unused spray solution.

Fusarium Wilt (Fusarium oxysporum f.sp. basilici)

Fusarium wilt is very difficult to manage as it can persist in the soil or hydroponic system for many years. Practice strict sanitation. Begin with disease-free seed or treat seed with hot water or dilute chlorox. The basil varieties Nufar and Aroma 2 have resistance to Fusarium wilt. Fusarium is a soil inhabitant that can become established in the field. Promptly remove and destry all infected plants, infested soil, and plant debris. Rotate crops, excluding members of the mint family, which can be symptomless carriers of Fusarium.