Spring time or not?

With the Kansas weather fluctuating between warm and cold temperatures lately, gardeners wonder what exactly what we can expect for our plants.  Kansas is well-known for extreme weather, both hot and cold, so what are we gardeners to do?

Have patience

Patience is a virtue and all Kansas gardeners get plenty of opportunities to practice their patience.  Waiting for consistent spring-like temperatures can be frustrating, but it is a must for many of our favorite garden vegetables and flowers. 

Soil temperatures in our area are still in the low 50’s which means we are still a couple weeks away from planting warm season vegetables and flowers.  Most warm season plants such as tomatoes, peppers, squash, and many of our favorite annual flowers require soil temperatures of at least 55 to 60 degrees to be able to start growing.  Planting them into cold soil actually does more harm than good. 

Cold nights can still be expected as our average frost free date is not until April 18-21st in central Kansas.  Even after this date, there is still a low chance of a late spring freeze.

Landscape plants

Plants in certain microclimates such as a south or west exposure where soil has warmed are likely already actively growing.   These may be candidates for protection from freezing temperatures if they are sensitive to cold and freeze or frost watches or warnings arrive in the forecast.   For more information on protecting plants from spring freezes see this post.

But keep in mind that most temperate zone plants survive our spring weather fluctuations well.  If buds are beginning to open it is helpful to note whether they are flower buds or leaf buds when considering any possible side effects from the cold.   Flower buds open first on some plants and if these get damaged the only loss is the loss of blooms and this doesn’t harm the plant.   If leaves are growing and get caught by a hard freeze, the cold damage can cause a delay in growth, but healthy plants develop secondary buds and grow out of the damage later on. 

Fruit

Fruit trees that are in bloom are often more of a concern to growers since freezing temperatures during the latter half of spring can kill the fruit buds and cause the loss of the crop.  Peaches and apricot trees bloom the earliest and are the fruit trees most frequently caught and damaged by a spring frost in Kansas.  Some fruit trees are in various stages of flowering right now, so any cold damage they receive will depend on how far along the fruit buds are in their stage of growth.  Apple tree blooms can generally tolerate temperatures down to about 28 to 29 degrees with little loss. See this post for more information on cold damage to fruit.

Vegetables

The table below lists vegetables and their tolerance to frost:

Vegetable	Frost Tolerance
Asparagus	Hardy
Rhubarb	Hardy
Beans, Snap	Tender
Beets	Half-Hardy
Broccoli	Hardy
Brussels Sprouts	Hardy
Cabbage	Hardy
Chinese Cabbage	Hardy
Carrots	Half-Hardy
Cauliflower	Half-Hardy
Cucumbers	Very Tender
Eggplant	Very Tender
Garlic	Hardy
Horseradish  Roots	Hardy
Kale	Hardy
Kohlrabi	Hardy
Lettuce,	Half-Hardy
Muskmelon	Very Tender
Mustard	Hardy
Onion	Hardy
Okra	Tender
Parsley	Half-Hardy
Parsnip	Half-Hardy
Peas	Hardy
Peppers	Tender
Potatoes	Half-Hardy
Pumpkin	Half-Hardy
Radish	Hardy
Rutabaga	Hardy
Salsify	Half-Hardy
Spinach	Half-Hardy
Squash, Summer	Very Tender
Squash, Winter	Very Tender
Sweet Corn	Tender
Sweet Potatoes	Very Tender
Swiss Chard	Half-Tender
Tomato	Tender
Turnips	Hardy
Watermelon	Very Tender

What to do

When it comes to Kansas one of the best things gardeners can do is to plant a diversity of plants.  For instance, the best way to ensure some fruit production each year in Kansas is to have a diverse fruit planting including hardier fruit trees such as apple and pear since peach, nectarine, cherry and apricot are more likely to be damaged by spring warm ups that are followed by a cold snap. 

It is also important to monitor soil temperatures and plant vegetables and flowers only when the soil temperature is adequate for vigorous growth for the particular crop or flower.

We can’t control the weather or when our plants are triggered to begin the spring growth process but we can ensure that our plants have the moisture, mulch, and any needed pruning and care that will keep them in healthy condition and free from other stressors.   Contact the Extension office if you have questions on your particular plant.