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Extension > Local Extension Offices > Stearns > County Horticulture Educator > Articles > Planting Bulbs in Fall

Planting Bulbs in Fall

University of Minnesota Extension, Stearns County News
September 23, 2015

Source:  Beth Berlin, Extension Educator-Horticulture
University of Minnesota Extension
Stearns, Benton & Morrison Counties


Planting Bulbs in Fall
By Beth Berlin, University of Minnesota Extension

ST. CLOUD, Minn. (09/23/15) —  Fall is officially here and now is the time to plant your spring flowering bulbs. Planning, purchasing, and planting bulbs now will provide an array of beautiful colors in your yard next spring.  Here is some helpful advice to have success with your bulbs. 

Tips for purchasing include checking for signs of disease or damage; this includes cuts or bruises.  The bulb should be firm and still contain its protective papery skin. Any bulbs that are soft or moldy should be discarded.

The time to plant bulbs varies, but most bulbs should be planted mid-September through first part of October. This is important so the bulb has a chance to grow roots before the ground freezes. However, tulips are an exception, they can be planted up till the ground is frozen and you can’t get them into the soil. 

Site selection is very important.  Select a site that will have the warmth and light of the sun to trigger growth in the spring and promote foliar growth after bloom. Adequate light after bloom will help the plant photosynthesize enough energy in the bulb and return next year.  Areas near building foundations with west or south exposure will likely warm up quicker and in turn the flowers will bloom earlier.  Mulching will help soil temps stay more consistent and help prevent cold weather damage to early emerging plants.  Another tip when selecting the site is to find a more protected area out of strong winds and avoid areas that are low and pool water and tend to have frost more often than other areas of the yard.

Site preparation is the next important step.  Loosen up the soil and rid of any roots, rock or debris. Blend in some organic matter such as peat moss, fine compost or shredded leaf mulch to the top 10-12 inches to improve the soil. This is also the time to add fertilizer; work in about 2-3 pounds of 5-10-10 fertilizer per 100 square feet. For smaller areas this equates to about a handful of fertilizer for 10 to 12 bulbs. Be sure to blend in the fertilizer; simply tossing it in the hole can actually lead to the fertilizer damaging the bulb or new roots.

Planting depth and spacing varies depending on the bulb variety.  A good rule of thumb is to plant two and a half times deeper that the bulb is wide.  However soil type may alter this recommendation. For example, on light sandy soil, plant the bulb one to two inches deeper than that recommendation, while in heavy, clay soil the bulb should be planted one to two inches more shallow than the recommendation.  Always plant the bulb pointed end up; press the bulb into the loosed prepared soil at the correct depth. Cover the bulbs with half the soil, soak with water, and then add the remaining soil. Finally water in and add three to five inches of leaf material, grass clippings, or straw as mulch. It is important to add this layer of insulation to keep soil temperatures more constant.  Typically the initial watering and normal fall rains is adequate moisture, however if fall is dry be sure to deep water the bulb area one or two times to help the bulbs establish good root systems before the ground freezes.

In spring, once the temperatures have warmed, carefully remove the mulch layer.  Keep a bag of mulch handy in case there is a hard frost in the forecast after you have removed the layers.  For more information about spring flowering bulbs visit www.extension.umn.edu and type “spring bulbs” in the search box.
 

 

Photo: Tulip;  Source: Bigstock

Contacts

Beth Berlin
Extension Educator, Horticulture
(320) 255-6169
adam0062@umn.edu
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