Garlic is a hardy bulb grown for its pungent cloves, used in cooking and storable for months after curing. In Zone 6b it is planted in fall, overwinters in the ground, and is harvested the following summer, making it a low-maintenance crop that occupies beds through the off-season.
Plant individual cloves, pointed end up, in fall about 6 weeks before the ground freezes so roots establish before winter. Hardneck types suited to cold climates produce a flower stalk (scape) in early summer; remove it to direct energy into bulb growth. Harvest when the lower leaves brown but several upper leaves remain green.
White Rust
White, blister-like pustules on the undersides of leaves with yellow spots on the upper surface; severe infections distort leaves and stems.
Remove and destroy infected leaves, improve air circulation, avoid overhead watering, and rotate brassicas to a new bed each year.
Botrytis (grey mould)
Grey fuzzy mould on petals and stems, worst in cool wet conditions.
Remove affected parts immediately. Improve air circulation. Avoid overhead watering. Apply copper fungicide if severe.
Downy mildew
Yellowing on top of leaves with grey-purple fuzz underneath. Spreads rapidly in humid conditions.
Remove affected leaves. Improve air circulation. Avoid overhead watering. Copper spray as preventive.
Garlic Basal Rot
Yellowing and dieback of leaves from the tips, stunted plants, and soft brown decay at the base plate of the bulb, often with pink-white fungal growth on roots.
Plant disease-free cloves in well-draining soil, rotate alliums on a 4-year cycle, avoid overwatering, and discard infected bulbs rather than composting them.