Spring onions are very easy to grow and with a little planning you will never run out. If you don't succeed at first try a different species or variety. I've had some pitiful results with welsh onion. Find out what works in your garden.
What are scallions, then? Are they the same as eschallots, salad/spring/green onions or shallotts? It seems to vary from country to country and who you talk to, so do double check that you get the right variety at the green grocer's.
This is a fast growing and hardy plant that can be cultivated in between other plants to fill in space.
Starting: Sow seeds directly and close together, then press the soil down. They like the firm soil. The seedlings will show in about a fortnight. Make successive plantings throughout the season for a continuous supply.
Soil: Scallions prefer an alkaline soil. Well drained loam or compost with some added lime will do the trick. Mushroom compost which is alkaline can also be used.
Climate: Can be grown year round in frost free areas.
Watering: Keep the soil moist but not wet.
Fertilizing: They don't like too much nitrogen, so go easy with the chicken poop.
Harvesting: Carefully thin when pencil size without disturbing neighbouring growing scallions. Harvest in eight to twelve weeks.
Containers: Any container with a depth of 15 cm. The roots are quite shallow as you might have noticed while perusing the greengrocer's display.
Shady areas: Will grow in shady conditions. In my shady courtyard scallions are one of the better performing plants.
Pests and Diseases: Not many problems, but slugs and snails attack occasionally.
Indoors: The plant grows happily in a pot on your windowsill.