Rutabagas are often confused with turnips because both are root vegetables, but rutabagas are larger, sweeter and have a less intense flavor. Rutabagas are so popular in Sweden that they are often "Swedes." The most popular variety grown in this country is the American purple top.
Rutabagas like soil that is loose, fertile and slightly alkaline. If the soil is more acidic, work some lime into the bed a few months before planting. Enrich the soil with compost, turning it into the bed with a rake. Remove any large rocks that might impede the growth of the roots. Finally, add a half cup of 5-10-10 fertilizer for every 20 square feet of garden space.
Rutabagas mature into large, round softball-size roots, so they need some room to grow. Use a hoe to create rows of small raised hills, spacing the rows 10" apart. Once formed, be sure not to compact the soil in the hills. Lay down a thick layer of mulch between the rows to hinder the growth of weeds.
Time the planting so that the harvest comes at or around the region’s fall frost date. Rutabagas mature in about 80 to 100 days, so use those figures when deciding when to plant. Sow the seeds 1/2" deep in the rows and 2" to 4" apart. Gently press the seeds into the dirt and cover them with soil. Carefully water the seeds and place a garden marker to indicate the crop.
Maintain constant moisture until the seeds germinate. Rutabagas sprout in about a week. A couple of weeks after the plants have sprouted, thin the seedlings down to just one every 8". Add a thick layer of pine mulch around the base of the plants, but do not let the mulch come in contact with the stems. Rutabagas need a steady supply of water to encourage steady growth of the roots. For an added boost, apply a dose of liquid fertilizer to the young plants.
Harvest rutabagas when they get slightly larger than a tennis ball. Like most vegetables, they are more tender the smaller they are. Rutabagas are very hardy and will easily survive frosts, especially when well mulched. Many gardeners leave the roots in the ground well into winter, pulling only the plants they want to eat. Others store them buried in sand in a cool, dry and dark place.