Although Mother Nature imposed delays during much of April on the start of the outdoor gardening season, listeners to a Wisconsin Extension Service webinar nonetheless got into the mood for a new growing season thanks to a webinar program titled "Planning for a Successful Gardening Year."
Presenter Mike Maddox, a horticulturalist who is the director of the Wisconsin Master Gardener program, reviewed a variety of factors pertaining to gardening practices for the raising of foods and fielded lots of questions from webinar attendees in county Extension Service offices around the state.
Maddox noted that a special question and answer session will be held from 10 to 11 a.m. Wednesday, May 7. Access details are available at Extension Service offices or through the fyi.uwex.edu/peopleplants website, which also has other relevant information.
A good starting point for gardeners hoping to grow and harvest food is to be aware of the probable killing frost-free periods in the local area, Maddox said. He cited averages running from the last week of April in southern Wisconsin to the first week of June in the north for the last killing freeze in the spring and from the latter half of September to mid-October respectively for the first killing freeze in the north and south.
In some years, those dates mean a growing season of only 90-100 days in the north to as many as 170-180 days in southern Wisconsin, Maddox observed. Those limitations or possibilities ought to be considered in choosing what types of garden plants to grow and even to select varieties within those species.
Those differences also allow gardeners to start and perhaps end the season by growing cool season crops such as peas, spinach and members of the brassica family, Maddox said. He emphasized that warm season plants such as beans, corn, tomatoes, peppers and melons should not be seeded or transplanted until the soil temperature has reached 60 degrees and nighttime temperatures don't fall below 50.
When transplanting, choose a cloudy day or protect the plants with a cover such as a tile to allow them to become more established before facing a full day of warm sunshine. Even before then, be sure to acclimate those plants to the outdoors for up to two weeks through gradual transmission from their protected indoor sites and, except for tomatoes, do not place them any deeper in the soil than they were in their starter pots, he emphasized.
Because of the number of days they need to mature, plants such as tomatoes, peppers and eggplant should not be started with seed in the outdoors, Maddox said. They, along with the brassicas, should be given a good start indoors by the grower or purchased from commercial outlets for transplanting.
With pumpkins, be aware that many of the varieties need 100-120 days to mature, Maddox cautioned. Because of problems with root establishment, he does not recommend transplanting melons or other vined plants.
Depending on the amount of garden space and what the grower intends to do with the produce, planters should also give attention to the differing traits within plant species, Maddox said. He listed the choices of bush or pole beans, bush or vined running plants, determinate or indeterminate tomatoes, dwarf plants and fruit size differences.
Some growers might prefer heirloom varieties over hybrids for reasons of taste, but they should also realize the heirlooms are more prone to disease, insects and loss in storage, he said. What gardeners, especially those who don't want to apply chemicals to their plants, should do is check the seed catalogs and packets for the level and type of disease resistance of the individual cultivar.
Maddox noted that garden plants are either classic hybrids or heirlooms, not the genetically-modified organisms that are now prevalent among the major field crops.
To a question about organic plants, Maddox explained there is no difference in the genetic traits of the seeds or the cultivars. The only difference is the seeds were obtained from organic production methods.
Based on the combination of the times of the growing season when plants grow best, the differing traits within the plant species and how the gardener wants to use the produce, there are succession planting strategies that can be carried out quite easily, Maddox said.
As an example, he cited a series of 55-day maturity beets, 52-day bush beans and then another planting of beets on the same ground during a growing season. As a way to deter pests, attract pollinators and fend off diseases, consider the interplanting of potatoes and cabbage or other combinations, he suggested.
Gardeners who intend to donate to a food pantry or sell at a farmer's market should have staggered planting dates such as one, three and six weeks apart, Maddox suggested. Another possibility is to plant beet varieties with 55- to 80-day maturities on the same day.
As with field crops, there are benefits in rotating what crops are grown on a given piece of ground from year to year. Because they have some similar traits, including the susceptibility to certain diseases, those benefits are not likely when rotating tomatoes, peppers and potatoes with one another, he reminded gardeners.
Because of the proximity that's necessary to accommodate pollination, corn needs to be planted in a patch or block. In all cases, follow the seed package directions on what the density of the plants should be, Maddox added.
Another essential consideration, particularly on plant spacing, is to provide for good air flow, thereby limiting the chances for the outbreak of diseases that thrive on excess periods of moisture on the plants, Maddox explained. Having access to full sunlight is also important for some garden plant species but not for others.
In addition to gaining some protection against both diseases and insects, realize that beans and peas add nitrogen to the soil for other plants in the same or following year, he said. Consider ideas such as leaving a portion of the garden fallow for a year and growing cover crops.
For cover crops, Maddox likes fast-growing ones such as oats and buckwheat rather than winter rye or winter wheat toward the end of the growing season, in part because the oats and buckwheat will not survive the winter. He mentioned the possibility of planting the oats very close to existing plants if the oats will not interfere with the remaining growth or the maturing of the produce on the other plants.
To reduce the likelihood of early blight in tomatoes and related species, placing a mulch around the plants is a good practice, he said, as late blight continues to be a threat.
Straw, mulches, layers of newspapers, landscape fabric and grass clippings on which no herbicides have been applied are good choices for weed control and preserving moisture, Maddox said. Wood chips are not a good choice because they consume available nitrogen as they decompose. Also, use pine needles as a ground cover only around ornamentals, he advised.
For livestock manure, opt for that which has been composted and apply it in the autumn. Other possibilities are coconut shells and husks and cocoa and chocolate beans, but the latter are poisonous to dogs, he warned.