I got back from a trip to Indianapolis over the weekend and found hellebores in bloom at Sandhill Gardens. This is a signal that I have work to do. The foliage from last year needs to be cut, and as the new foliage come up, it makes it difficult to cut the old. It is time-consuming, but it is best to use some sharp scissors or pruners and cut one stem at a time. Trying to shear off clumps will almost certainly result in cutting off flowers and the foliage for this year. The good news is that this is the only real care the hellebores will need for the year, unless I decide to dig some and re-plant them. For this work, they will reward you with blooms that sometimes continue into July and nice foliage that adds a different texture to shade gardens. I have a couple of clumps that have variegated foliage, adding another form of interest.
In addition to the hellebores, winter aconite and some early crocuses are in bloom. These are tough flowers, and though very cold nights may cause them to wilt down, it will not kill them. Actually, the cooler weather will cause the blooms to last longer.
In a recent column, I gave instructions for winter sowing of seeds that need a cold treatment for stratification. Now, it is getting time to begin sowing seeds for tender plants. This must be done inside or in a hot bed, as these plants will not survive freezing temperatures. For vegetables, including tomatoes, peppers and eggplant, count back six weeks from our frost-free date to get the date to sow them. May 10 has traditionally been that day of being safe from freezing temperatures, but it has been a long time since we have had freezes that late. Also check the “days to germination” information on the seed packet. Some peppers are slow to germinate without bottom heat, so they may need to be sowed earlier. If you do not have a heat mat on which to set them, you may want to put the trays on top of your refrigerator until they have sprouted.
Caring for the seedlings inside can be a challenge. Started too early, they tend to get spindly before time to set them out. This is usually because they do not get enough light. If you want to grow good transplants, consider purchasing a grow light with a timer. Leave the light on for about 16 hours a day to give the plants the light they need to develop properly. If you have a sunny window, you may be able to grow without a grow light, but, just as the houseplants we discussed last week, they will need to be rotated frequently to keep them growing straight. The plants will grow toward the sun, which means they will grow toward the window. Keep an eye on them. They may need to be turned more than once a day!
I have had some questions concerning cold frames and hot beds, and how they are different. In general, they are the same on the surface, but a hot bed has a heat source. Usually, rotting manure in the bottom of the bed supplies heat. If you wish to build a hot bed, dig down about a foot. Fill that area with fresh manure. Horse manure is favored by many, as it gets hotter than some other manures. Then you need to build a frame around the bed, and fill the frame with compost or garden soil. The bed then must be covered with glass or clear plastic to hold that heat in. You have to watch the bed daily. If it is a sunny day, the temperature in a hot bed may get too hot, and you will need to open the top. The outside temperature will be the deciding factor on just how much to open the bed. Sometimes, it just needs to be open a few inches for ventilation, and other times it needs to be fully open. Just be sure to close the lid if freezing temperatures are predicted at night.
Crops like cabbage, lettuce, broccoli, cauliflower and related crops do quite well in a cold frame, but tomatoes, cucumbers, squash and other warm-season crops will need the heat of a hot bed if you wish to start the seeds early.