Shallot

Plant sets or seed as soon as the ground can be worked

Work compost and a complete fertilizer into the top 6 inches, then plant bulb sets 1 to 2 inches deep in early spring as soon as the soil is workable. Space sets 3 to 6 inches apart in rows 12 to 18 inches apart; sow seed 1/2 inch deep and thin to 2 to 4 inches. Tight spacing gives you single bulbs, wide spacing gives clusters of 10 to 15. Shallots need to build leaves before day length triggers bulbing, and every leaf standing at that moment becomes a ring of bulb, so a late start costs you size you cannot get back.

Optional fall planting for an earlier crop

Where winters are mild enough that the ground does not heave, set shallot bulbs after the first frost, 1 to 2 inches deep, for a late spring harvest. Mulch the bed once the ground chills. Fall sets overwinter as small rooted plants rather than pushing much top growth. Bulbs set in autumn root through winter and start leaf growth the moment soil warms, which puts more leaves on the plant before bulbing begins than a spring planting can manage.

Steady water through bulbing, then cut it off

Keep the soil near field capacity, moistening thoroughly to 8 to 12 inches; if the bed does not get an inch of rain a week, soak it thoroughly at least once a week. Use drip if you can and water in the morning rather than at night. Mulch to hold moisture and hold weeds down. Stop watering once bulbs have reached full size and the tops begin to fall. Shallots are shallow-rooted and need constant moisture, so the plant cannot chase water down the profile and bulbs sized under drought stress stay small. Wet foliage overnight is what lets Botrytis and downy mildew get started.

Side-dress nitrogen twice, then stop before bulbing

Side-dress about 1/2 pound of 21-0-0 per 100 square feet roughly 30 days after planting and again at 60 days, watering it in. Then stop. Do not keep feeding once the tops are up and bulbs begin to swell. Nitrogen late in the season pushes leaf growth at the expense of the bulb and leaves thick, soft necks that never cure tight, which is exactly how a stored crop rots by midwinter.

Count thrips in the necks as bulbs size up

Once plants have at least 4 to 5 leaves, pry open the necks of about 50 plants across the bed and count the tiny straw-colored thrips before they scatter. Treat only if you average more than 15 per plant early or more than 30 per plant once bulbs are enlarging. Straw mulch, overhead sprinkling and clearing weedy debris and volunteer onions all knock populations back without a spray. Thrips rasp chlorophyll out of the leaves, and leaf area lost during bulb enlargement is bulb size lost. Counting matters because 60 to 75 percent of the population is eggs sunk inside leaf tissue where nothing you spray can reach them, so spraying on sight just kills the generation you can see.

Onion thrips: spinosad only once counts pass threshold

If counts exceed threshold during bulb enlargement, spray spinosad, directing it down into the center of the plants. Use high pressure and high water volume, which penetrates better into the inner neck where the thrips actually sit. Azadirachtin, kaolin clay and insecticidal soap are weaker alternatives. Rotate to a different mode of action between applications rather than repeating spinosad. Thrips shelter in the tight neck of the plant, so a spray that only wets the outer leaves misses most of them and selects for the survivors. Onion thrips have already developed widespread resistance to organophosphates and pyrethroids across the western US, which is what repeated same-class spraying buys you.

⚠ Spinosad is toxic to bees and to predatory mites and syrphid larvae while wet and for about a day after; do not apply it to anything in flower, including flowering weeds in the bed, and spray in the evening when bees are not foraging. Check the label for registered uses and the pre-harvest interval before you spray.

Row cover against onion maggot, but only on rotated ground

Cover the bed with floating row cover at planting and seal the edges to keep egg-laying flies off the plants. Do this ONLY if no onions, shallots, garlic or leeks grew in that spot last year, and site the new bed as far from last year's allium ground as you can. Bury or destroy every cull bulb and volunteer instead of leaving them in the garden. Onion maggots overwinter as pupae in the soil right where their host grew, so cover laid over infested ground traps the emerging flies with your crop instead of excluding them, and cull piles are where the spring generation is born.

⚠ There are no insecticides available to home gardeners as a pre-plant treatment for onion maggot, so exclusion and rotation are the whole toolkit.

Lift when the tops flop, then cure until the skins rustle

Pull green shallots any time the tops are 6 to 8 inches tall, about 50 to 60 days in. For dry bulbs, wait until the tops fall over on their own, then lift the plants and break the clusters into individual bulbs. Cure them 1 to 2 weeks until the leaves and skins are papery and the necks are tight, then store at 32 to 40 degrees in mesh bags. The tops falling is the plant closing the neck and moving the last of its reserves into the bulb; lift before that and the neck stays open, which is the door every storage rot walks through.