Soil temperature allowing for planting

In the Garden
Ralph Purkhiser, Purdue University Master Gardener

     While the threat of freezing weather is still around for another month or so, each week the soil temperature is climbing.  That means some hardy vegetables may be safely planted in the garden.
     If you have not already done so, you may sow seeds for most lettuces and salad greens.  These plants thrive in the cool spring weather and will bolt and set seed when the weather gets too hot.  The flavor is also at its peak during cool weather.  Most salad greens turn bitter with heat.
      Brassicas also enjoy the cool weather.  Brassicas include all types of cabbage, cauliflower, broccoli and Brussels sprouts.  Although the brassicas do not bolt as quickly as the salad greens, the milder, sweeter taste comes when they are grown in cool weather.  Transplants are now available at most nurseries and garden centers, but there is still time to start your own from seed if you cannot find transplants for your preferred varieties.  Save back some seed to start in late July for fall brassica crops.
     You may plant peas at any time now.  They will make it through some frost, but keep some cover available should temperatures drop to the low 20’s.  All peas have a vining tendency, so plant them where they will have a structure on which to climb.  The trellis does not need to be fancy—just something to support the vines.  It not only makes them easier to pick, it helps keep the plants out of the mud, protecting them from rot.
      You may also plant potatoes whenever your soil is dry enough to work.  Like the peas, the potato foliage will survive frost, but will need protection if we get a hard freeze.  If the wet soil is delaying your planting, you may grow potatoes in large containers or on top of the ground, surrounded by some type of sleeve.  Simply place the seed potato on the ground and cover it with some compost.  As the potato sprouts and grows leaves, add more compost or organic matter, such as straw or shredded leaves.  When the plant reaches the top of the container and blooms, the vines will start to die.  You may then remove the container and rake back the compost.  You will find nice, clean potatoes lying on the ground.
     While you may find transplants for tomatoes, peppers, squash and other summer vegetables in some garden centers, it is far too early to put them in the garden.  Even if you use protective cloches, the soil temperatures are not warm enough to promote good root establishment.  Keep those plants growing inside until May 10, when the danger for frost is past and the soil has warmed.
      You may begin planting corn and beans in late April, but be careful not to put them out too early.  The seeds need warm temperatures to sprout and may actually rot if planted too early.  The same is true of sweet potatoes, which want the soil to be even warmer.  Rushing things can be counter-productive.
     You will also find some spring flower transplants in the garden centers.  Add some pansies or violas to your garden beds.  You can even add the flowers to you spring salads.  They will give your salad some nice color and a peppery taste.
     You will also find some potted tulips, daffodils and other spring bulbs.  These are fine for filling in some pots for a while, but they are not likely to return next year.  These bulbs have been forced and that process takes a lot out of the bulb.  Even if the bulb produces foliage next year, it will not likely produce flowers for a couple of years.  I, personally, go ahead and plant them if I receive some as gifts, but I rarely buy the forced bulbs.  Most experts will tell you to just throw them on the compost pile when they have finished blooming.
     The flowers have been spectacular at Sandhill Gardens this spring and I am sure your garden has been pretty also.  Take time to sit out there and enjoy it.