Growing turnips and rutabagas in home gardens

• Have your soil tested. 
• Turnips thrive in slightly acidic to slightly basic soil with pH levels 6 to 7.5. Rutabagas will grow best in slightly acidic to neutral soil with pH levels 6 to 7.
  • Apply phosphorus (P) and potassium (K) according to soil test recommendations.  
  • Many Minnesota soils have enough phosphorus. Unless your soil test report specifically recommends additional phosphorus, use a low- or no-phosphorus fertilizer.
• Improve your soil by adding well-rotted manure or compost in spring or fall. Do not use fresh manure as it may contain harmful bacteria and increase weed problems. The readily available nitrogen can also cause branching of the roots. 
  • If you use manure or compost, you may reduce or eliminate additional fertilizer applications, depending on how much organic matter you apply.
• One month after planting, side dress rutabagas with fertilizer, using one-half cup of 46-0-0, or one cup of 27-3-3, or 3-½ cups 10-3-1 for each 100 feet of row.
• Turnips do not need more fertilizer than the initial pre-plant application.
• Do not use any fertilizer containing a weed killer ("Weed and Feed"), as it may kill your vegetable plants.

• Plant turnips beginning April 15 for a spring crop, and again August 1 for a fall crop.

  

• Rutabagas require a longer growing season, but need to mature in cool weather, so you should plant them from late May to early June for a fall crop.
• Plant seeds one to two inches apart in rows 18 to 30 inches apart.
• Seeds of both species will germinate quickly. Look for seedlings to emerge after about ten days.
• Once true leaves have emerged, begin thinning the seedlings to allow room for root development.
  • Thin turnips to a spacing of three to six inches between plants, depending on the size of root you want to grow.
  • Thin rutabagas to an eight-inch spacing. Be sure to pull any weed seedlings at this time, too.

    

• Although the storage root of these plants can be large, they do not have extensive root systems for absorbing water.
• The plants need to receive one inch of water per week, whether from natural rainfall or from irrigation. Drought stress can make them bitter or woody.
• Always soak the soil thoroughly when watering. This helps to promote good root development.
• If your soil is sandy, it is important to water more often than once a week.
• An inch of water will wet a sandy soil to a depth of ten inches, a heavy clay soil to six inches.
• Use a trowel to see how far down the soil is wet. If it is only an inch or two, keep the water running.
• Excessive rain is beyond the gardener’s control, but rutabagas will have more flavor, be firmer and store better after a relatively dry growing season than a wet one.

• Frequent, shallow cultivation will kill weeds before they become a problem.
• Turnips and rutabagas form roots very close to the surface of the soil. Cultivate just deeply enough to cut the weeds off below the surface of the soil.
• Be careful not to damage the plants when cultivating.
• Mulching with herbicide-free grass clippings, weed-free straw or other organic material to a depth of three to four inches can help prevent weed growth, decreasing the need for frequent cultivation.

• Root maggots feed on the developing roots. 
• Flea beetles chew small, round holes in leaves. They can spread disease and destroy the crop, especially when the plants are very young.

Turnips

• Harvest turnips when they reach a usable size, normally about two to three inches in width.
• Their shoulders are usually above the soil surface, so it is easy to tell how big they are.
• As the roots become larger, they are more likely to become bitter, strong-flavored, woody or fibrous.
• Spading the soil next to the plants will make them easier to pull.
• You can harvest the greens or “tops” of turnips and cook them as a savory vegetable.
• Cut the greens from the roots when you harvest the turnips, wash them and store separately. You can also use the greens when you thin crowded plants, before the roots begin to enlarge.

Rutabagas

• Leave rutabagas in the ground until September, October or even later.
• Frost improves best flavor, so many gardeners wait until after at least one hard frost to dig them up.
• The roots can be quite large. Rather than trying to pull them up, it is best to dig them with a spading fork.

Turnips

• Separate the turnip greens from the roots.
• Clean and store both roots and tops in the refrigerator for a week or two.
• Turnips lose moisture rapidly and you cannot store them long-term.

Rutabagas

You can keep rutabagas for a long time in root cellar conditions: 32°F to 40°F, and 95% relative humidity. Under root cellar conditions, you can store rutabagas for up to five months. Remember that after a wet growing season, storage life is likely to be shorter.

If you plan to store them in the refrigerator, the rutabagas may sprout after a few weeks. The relative humidity in a modern refrigerator is quite low, so the roots may dry out.

To increase storage life, delay harvest as long as possible. Rutabagas will keep their quality in the ground for weeks. Once you harvest them, remove the tops and the long, thin taproot. Clean dirt off the skin, being careful not to cut or bruise the roots.

Grocery stores usually sell rutabagas with a coating of paraffin wax. This coating keeps them from shriveling on the display shelf. It is not part of long-term storage practice.

• Flea beetles chew small holes in leaves. Seedlings are most vulnerable to injury from this feeding. 
• Cabbage maggots feed on the roots, tunneling through turnips.

Many of the same cultural practices help prevent a wide variety of turnip and rutabaga diseases. 

• Alternaria is a common disease that causes spots on leaves.
• Black rot causes yellow triangles on the edge of leaves, and can cause plants to rot.
• Clubroot attacks the roots, causing roots to become stunted and small.