Growing shallots in containers works well as long as you pick the right pot and soil. Use a container at least 8 inches (20 centimeters) deep with drainage holes in the bottom. This depth gives the roots all the room they need to spread out and feed your bulbs through the season.
I tried growing shallots in pots on my balcony using a 14-inch (35-centimeter) terracotta pot. I fit 6 sets in that single pot with 4-inch gaps between each one. Every set produced a cluster of 5 to 8 bulbs by harvest time. The bulbs came out a touch smaller than my in-ground crop but the flavor was just as strong. I've used this method for three seasons now and it works great for anyone with limited garden space.
These plants are a natural fit for pots because they have short root systems. According to Johnny's Selected Seeds, the roots stay in the top 6 to 8 inches of soil. That makes shallots in pots a better bet than carrots, parsnips, or potatoes that need much deeper containers. You don't need a huge pot to grow a solid crop of tasty bulbs.
The Royal Horticultural Society talks about growing in pots but skips the key details. They don't list specific pot sizes or soil mix ratios. They also skip watering tips for pots versus garden beds. Those details matter a lot. Potted plants dry out faster and need more food than crops growing in the ground.
Your soil mix makes or breaks your container crop. Blend 60% potting soil with 40% perlite for fast drainage that still holds moisture between waterings. Straight potting soil packs down too tight and chokes the roots. I tested both mixes in side-by-side pots last season. The perlite blend made much bigger bulbs with stronger roots.
Space your sets about 4 inches (10 centimeters) apart in the container. This is tighter than garden spacing but works fine in pots since you control the nutrients going in. Push each set into the soil with the pointed end up and the base about 1 inch below the surface. Water the pot well right after planting and place it where it gets 6 to 8 hours of sun per day.
Container shallot care takes more attention to watering than ground growing. Check your pots every day during warm weather. Water when the top inch of soil feels dry to your finger. Don't skip your daily check since pots can dry out fast on hot days. Feed with a balanced liquid fertilizer at half strength every 2 weeks through the growing season.
I found that terracotta pots dry out faster than plastic ones in summer heat. If you use terracotta like I do, you may need to water twice a day when temps climb above 85°F. Plastic pots hold moisture longer but don't look as nice on a patio. Pick what works for your setup and adjust your watering to match.
Good container shallot care also means watching for signs of stress. Yellow leaves in mid-season often point to too little water or food. Move your pots to a spot with afternoon shade if temps climb above 85°F (29°C) for days in a row. Your container bulbs need the same 90 to 120 days as ground-planted ones to reach full size.
Harvest your container crop once the tops turn yellow and fall over just like you would in a garden bed. Tip the pot on its side and slide the soil block out. Brush off the loose dirt and lay your bulbs in the sun for a few hours before curing. You can reuse the same soil mix next season by adding a handful of fresh compost and perlite to top it up.
Read the full article: Growing Shallots: Key Tips for Success
