Small garlic bulbs come from five main causes in most home gardens. Not enough cold time, planting small cloves, poor soil, too little water, and harvesting too early all play a role. Any one of these factors can keep your bulbs from reaching full size at harvest time.
I went through this same puzzle my third year growing garlic in a new garden plot. My bulbs came up tiny despite good care all season long. After some testing, I found out my sandy soil was running out of nitrogen by April each year. A spring side dressing of blood meal fixed the problem and doubled my bulb size the next season.
The size of your seed cloves matters more than most growers know for why is my garlic small problems. UMD Extension research shows that large cloves make larger bulbs than small cloves from the same parent bulb. Always plant the big outer cloves and save the small inner ones for cooking instead of wasting garden space.
Cold weather plays a key role in garlic bulb size problems for hardneck types you grow. The plants need 4-8 weeks of temps below 50°F (10°C) to trigger proper bulb formation in spring. Warm winter areas may not give garlic the chill time it needs to divide into cloves and size up.
Soil that lacks nutrients leads to underdeveloped garlic even when other factors are fine. Garlic feeds heavy on nitrogen in spring when leaves are growing fast above ground. Side dress with compost or a balanced fertilizer when shoots reach 6 inches tall to fuel the bulbing phase that comes next.
Water stress during the last month before harvest shrinks bulbs more than any other time. Keep soil moist but not soggy through May and June in most regions of the country. Dry soil signals the plant to stop growing and start curing before bulbs reach their full size potential.
Harvest timing affects final bulb size too for many growers. Digging too early leaves growth on the table. Wait until 40-50% of leaves have browned before you pull your crop. Those last few weeks add real weight to each bulb as cloves finish swelling up.
Review your whole process if you see small bulbs at harvest time this year. Check seed clove size, cold exposure, feeding schedule, water during bulbing, and harvest date. Fix the weakest link and you will see much bigger garlic next summer in your garden.
Read the full article: Growing Garlic Successfully in Any Climate
