By Linda Wiggen Kraft, Green & Growing Editor
March is springtime, not just for the official day of spring, but for the time seeds can be planted for the garden. There are seeds that can be planted outside and seeds that can be planted indoors.
For outdoor planting there are vegetable and flower seeds that can go directly in the soil. Mid to late March is a safe time for their planting. These seeds will germinate at the right time and can survive snow fall and below freezing weather to 26°. If they germinated and are growing, and the weather drops below 26° they will have to be covered with a cloth until the temperatures warm up.
Vegetable seeds that can be planted in March do well in our cooler spring weather. Seeds that can be planted in March are: arugula, beets, bok choy, carrots, chards, collards, kale, kohlrabi, lettuce, mustards, parsley, peas, radish spinach, turnips. Seed St. Louis has a very handy chart showing when to plant vegetables not only in March but throughout the gardening season. It can be found near the bottom of their home page at https://seedstl.org/. Herb seeds can also be started in late March including cilantro, oregano and thyme.
Some flower seeds that also be planted outside in late March and a bit later. These are called hardy annuals. Bachelor buttons or corn flowers, calendula, Chinese forget-me-nots, fever-few, larkspur, love-in-a-mist, nasturtiums and poppy seeds (which include breadseed, icelandic, shirley). Poppy seeds are very tiny and need a very light covering of soil. Plant larkspur in early March, or before, when some freezing temperatures help the seeds to germinate. Although sunflower seeds germinate in warmer temperatures, I often throw handfuls into the winter garden for the birds. Some seeds will not be eaten and will germinate later, growing multiple stems on each plant with smaller flowers.
When planting seeds outdoors in early spring, and in transplanting already growing seedlings, the spacing of how large plants will grow is a concern. Cool weather plants can be planted in rows or with square foot gardening in both raised beds and on the ground garden beds. If planting in rows check the seeds package for spacing guides. One of the easiest ways to plant seeds with the appropriate spacing is to use Square Foot Gardening. Made famous in the 1970s, this way of planting has been popular since, especially for small gardens. Sectioning off garden beds into one square foot area of soil, different plants require different spacing. A template* is often used to plant different numbers of seeds spread out evenly in the space. Here are the number of seeds per square foot for the above veggie seeds: arugula (6), beets (9), bok choy (4), carrots (16), chards (4), collards, kale (1), kohlrabi (9), lettuce (4), mustards (9), parsley (4), peas (8), radish (16), spinach (9) and turnips (9).
I plant flower seeds indoors so I can have flowers that aren’t available at the garden centers. My most favorite are purple and peach cactus and large flowered zinnias. Queeny series zinnias are multicolored in each blossom. White star zinnias are small flowers for front of the border plants. I also plant tall ageratums, Chinese forget-me-nots, hyacinth bean vines, marigolds, nasturtiums, straw flowers and tobacco plants with purple flowers.
The most important part of planting seeds indoors 6-8 weeks before planting outside, is having enough light. If grow lights are available, that is the best option. Window sill light needs direct sun, which may work. The best soil mix used for seedlings is lighter that most potting mixes. There is a new one that is available that has no peat and mycorrhizal fungi. It is called 3-in-1 Seed Starting Mix and is widely available.
Let your spring garden start with planting seeds this March.
*Templates and charts for square foot gardening are available for pre-made and DIY instructions online.
Linda Wiggen Kraft is a landscape designer of holistic/organic gardens. She is an artist and creativity workshop leader. Her ceramic jewelry and pottery are available online and at www.gardendistrictstl.com. Find out more, subscribe to her blog and Instagram at www.creativityforthesoul.com Call her at 314 504-4266.