Why tulips grow best in cold weather

If you live in a cold climate and can’t wait to see your garden start to grow, you’ll probably be a big fan of tulips. Most other plants can't bear wintry weather, but tulips actually need cold conditions to prosper.

Tulip bulbs, also known as modified roots, follow their own rules when it comes to growing. Unlike other flowers that will start to bloom as the days lengthen with the coming of spring, tulips will only start to flower when they are ready.

Tulips also don’t like the heat given off by too much direct sunlight and usually won’t grow successfully unless the bulb is planted more than 8 inches deep in the soil. Taking all these picky preferences together, some people think that it’s almost impossible to grow tulips from the bulb at home.

The right temperature for tulips

The ideal temperature to grow tulips is below 55 degrees Fahrenheit. But there is such a thing as too cold for tulips: The plant has a temperature tolerance limit of 29 degrees. A few degrees below this level will destroy the tulip buds and flowers. If it reaches freezing, the whole tulip can be damaged. Tulips begin to show signs of growth at 60 degrees. Flowers and leaves start to appear at 68 degrees. Because of these precise needs, tulip breeders tend to refrigerate the bulbs so that they can plant them at the right time. In fact, tulips can be planted as late as early December and still enjoy spring blooms.

There are certain species of tulip bulbs that are perennials. These include the species Tulipa batalinii, T. clusiana, T. humilis, T. kaufmanniana and T.turkestanica. But, unlike most perennials, these tulips cannot be counted on to bloom every year once planted. In fact, most of these tulips will come back only a few years at best. If tulip foliage dies too soon after they bloom, dormancy sets in before another flower can form and none will appear the following year. Also, large tulip bulbs eventually wear out and produce young offsets that take several years before they flower.

How the pros grow tulips

Commercial tulip growers provide ideal conditions by digging up and storing bulbs in refrigeration. This is obviously difficult to replicate for the average home gardener. After the spring bloom — and for many tulips, this means late spring — there usually isn't enough time for foliage to manufacture and store food before the days heat up and send bulbs into dormancy. Tulips grow so well in the Netherlands due to the northerly latitude and chilly sea air that brings longer, cooler springs. In most home gardens, there is no guarantee that cool weather will last long enough for tulips to get the growing conditions they need.

How to plant tulips in your garden

If you are looking for a gardening challenge, a study conducted at Cornell University revealed some best practices to help you grow tulips at home:

1. Starting as early as December, clear away snow and loosen the soil as much as possible. Try to choose an area with soil full of organic matter.

2. Scratch in bulb fertilizer. If the ground is frozen, scatter fertilizer sparingly and over a larger range than normal.

3. Place the tulip bulbs on top of the soil. Do not press them in, as this will damage the bulb base where roots form.

4. Cover the tulip bulbs with 2 to 4 inches of aged mulch or finished compost. Go for the thicker layer if planting during the height of winter. Renew mulch covering often to be sure there is at least a two-inch layer.

Tulips are hard to grow at home. They require special conditions that are different from most other plants. But if you live in cold-weather conditions and are ready for a gardening challenge, tulips offer beautiful spring flowers that are worth the trouble and make for a rare and special addition to any garden.

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