In The Garden

Ralph Purkhiser, Purdue University Master Gardener

Spring planting time is well underway, but it is important to wait until the soil is ready for your plants. Several factors affect the planting time for different plants.

Temperature is a major factor in deciding when to plant. While trees, shrubs and perennials hardy to this zone will tolerate cool soils, tender plants, including vegetable starts and annual flowers, need for the soil to be warmer to thrive. Planted when the soil is too cool, the plants will, at best, sit there and not develop until the soil warms. On the other hand, some plants will develop problems, including root rot. The same is true of seeds. Some need warmth for germination, and planted too soon may result in rotting seeds. It is best to wait until the soil is warm enough for healthy growth.

Moisture is also needed for plant development and seed germination, but April showers often bring too much moisture. It is best to stay out of the garden when the soil is too wet. Make a ball of soil and drop it from about five feet off the ground. If the ball falls apart, it is dry enough to work the soil. If the ball remains intact, the soil is too wet. Walking on the wet soil will cause compaction that may plague you for a long time.

Soils are not equal. Clay soils tend to hold moisture longer, but are also more subject to compaction. Sandy soil will have good drainage, but may not hold enough moisture to promote good plant growth. It takes organic matter to improve the tilth of the soil. The easiest way to add organic matter is with compost. You may purchase compost or make your own. As I noted in the planting instructions last week, the best way to add compost is to put it on top of the soil surface and let the earthworms and insects in the soil incorporate it into the soil.

In the past, it was recommended to till compost into the soil, but tilling may be counter-productive. The soil contains many living organisms, and tilling may kill those organisms. Soil scientists have learned that certain fungi form a symbiotic relationship with the roots of plants. These are known as mycorrhizae. I will not pretend to know how mycorrhizae work, but they enable plant roots to take up minerals, and in turn, the fungi are nourished by products produced by the plants. Both organisms benefit from this arrangement.

This is one of the reasons that many farmers have converted to no-till operations, using a drill planter to plant seed with minimal disturbance to the surrounding soil. This practice has the bonus effect of reducing erosion of the soil. The easiest way to incorporate this practice in your vegetable patch or flower garden is to garden in raised beds. Not only are you able to control the soil used in the beds, but you may plant with minimal disturbance.

Friday, April 26 is Arbor Day in Indiana. It is a good time to plant a tree. If you do not have room in your landscape for a new tree, consider donating a tree to be planted in a park or other public space, or donate a tree to an area where wild fires have destroyed the forests. Planting a tree demonstrated your hope for the future.

I want to thank everyone who came and purchased plants last Saturday at the Hoosier Hillsides Master Gardeners’ plant sale in Orleans. It was a very successful sale, and I was able to meet readers from Orange, Crawford, Martin and Lawrence Counties. Enjoy your new plants.

It is time to take down the “Shhh, The Garden is Sleeping” sign.  I put that sign at the end of my walk every fall as a reminder that there is still activity during the winter months.  However, the garden is definitely awakening now.  This past week, the earliest daffodils began blooming at Sandhill Gardens.  The hellebores continue to put on a great show.  Each day, it seems another clump bursts into bloom.  I have been very busy getting the old foliage cut away, but still have some clumps to attack.  It really is the only thing I have to do to the hellebores each year, so, although it is time-consuming, it is worth it.

As we turn to March on the calendar, there are a lot more garden chores to do.  Over the weekend, I had some very capable help in the garden, and took advantage of that to put down cardboard and mulch in the bosquet I planted last fall.  (For those who may not have read that column, a bosquet is a circle of small trees, planted to create a garden room.)  A table made from a treadle sewing machine base is now in the middle of the bosquet.  I plan to place a bonsai specimen or some other potted plant there when the weather gets warmer.

You have probably seen articles and social media posts urging you to wait until temperatures are consistently in the fifties to clean up the garden.  The reason is that many insects over-winter in the debris from last year’s garden, and will not emerge until temperatures warm.  However, if I were to wait until temperatures reach that level, which will likely be in mid-April, I would never get everything done before it is time for other activities.  Therefore, I have started the clean-up.  However, most of the debris will be stockpiled at the edge of the woods, where the insects will still be able to live.  I may later chip up the debris and add it to a compost bin.

The fifty-degree rule is really a good suggestion, but gardeners should not feel obliged to wait to clean up the garden.  Do not feel that you are doing something wrong by cleaning your garden.  It is, after all, your garden.  I do encourage everyone to do what you can to help the environment, but cleaning your garden is not going to destroy the planet.  There are still going to be plenty of wild areas, at least in rural southern Indiana, so your garden represents only a small portion of the environment.  As for me, I will clean up areas near the house first, and move out from there.  The wildflower meadow and other edge-of-the-woods areas will be the last and will probably not be touched before the insects emerge.

My garden tends to be a little messy, but that means good habitat for the local fauna.  It is a certified pollinator garden and wildlife habitat.  However, that is my preference, and I would not expect everyone else to garden this way.  I have a friend who loves plants, birds and butterflies, but cannot stand clutter.  Her garden is very different from mine.  She likes individual plants to stay where planted, and the garden is more a plant collection than a habitat.  That is what she likes, and that is OK.

My point is that no individual home garden is going to wreck the world.  With the internet, there are crusaders who cling to a particular view and seem to wish to tell everyone else how to garden.  One of these issues is the planting of native plants versus using non-native or exotic plants.  My hellebores, hostas, daffodils and peonies are all non-native plants, but they are an important part of my gardens.  Even though I choose to include exotics in my landscape, I probably still have more native plants than the average garden.  After all, my favorite flower, the purple coneflower, is a native.

My advice remains to garden in a way that pleases you.  I do encourage you to limit the use of chemicals and avoid truly invasive plants, but do not feel that you have to garden in any particular fashion.  After all, any garden is better for the earth than no garden.  Have fun and enjoy this coming season.

Spring has finally arrived!!!  The cool temperatures are helping spring flowers to last longer, so the landscape is stunning right now.  In a well-planned garden, spring perennials provide a lot of color and food for early pollinators without a lot of work.  At Sandhill Gardens, the hellebores and daffodils continue to dominate the scene, but there are a lot of plants playing supporting roles.  The first of the flowering trees are in bloom.  The vivid pink of American plum and the delicate pink of the flowering cherries supply great contrast in a single color.  Various colors of crabapple and serviceberry are in tight bud and will soon open.  The first azaleas have bloomed in a vivid magenta.  Bloodroot’s bright white flowers have graced the shade garden, while purple and white windflowers fill in throughout the garden.  Lungworts continue to supply blue, pink and white accents, and the first of the bluebells have brought the sky to the ground.  Epimediums in red, pink and yellow give some airy quality to the shady areas.  Pink and blue muscari dot the lawn areas and hyacinths of white, purple and pink perfume the air.  It is really a magical time in the garden, and the work was done in prior years.

That does not mean there is nothing to do in the garden.  It is time to clear out the debris left from last year’s garden.  Where possible, cut stalks to about a foot tall, leaving the short stalk as a home for bees and other insects.  Those stalks will also provide some support for the young plants that will be growing in and hiding the stalks.

In the vegetable patch, it is tradition to plant potatoes on Good Friday.  It is also time to plant peas, which I prefer to plant along a fence or some type of trellis.  You may now safely plant cabbage and other cole crops and most leafy greens actually prefer the cool growing conditions of early spring.  Onion sets may also be planted any time now.     There is also still plenty of time for seeding tomatoes, peppers and other warm-season crops indoors.  Most seed packets recommend starting seeds six to eight weeks before the last frost date, but you may plant transplants in the garden as late as the end of June and still expect a harvest.  Of course, the harvest will be later, but that may be a good thing.  You may disrupt the timing of some pests.

I have received some questions concerning potting mixes that do not seem to be able to absorb water.  That is normal.  Many of the mixes are based on coir fibers or peat moss, both of which may dry out.  The dry mixes will be lighter, and that saves shipping costs for suppliers.  If you have mixes that do not seem to absorb water, you will need to stir in water before planting seeds.  I use an old fork and add water slowly.  When the mix is moist, but not soggy, it is ready for planting.  If you have a bag of soil, you may pour water into the bag and let it sit for a day or so.  It will absorb the water and be more hospitable to plants and seeds.  It is also important to keep soils moist to get good germination.  Check the planters every day.  Keep a close eye on anything you have on a heating mat, as the heat will cause soils to dry out more quickly.  If you have seeds already planted in dry mixes, you may be able to salvage them by placing the tray in a larger tray with some water.  The soil will absorb the water from the bottom.  Once the seeds have germinated, you will need to discontinue letting the tray sit in water, though you may water from the bottom and pour off what does not get absorbed in an hour or so.

Do not let the work keep you from enjoying the beauty of the spring garden.  As the poet, Robert Frost, noted, nothing gold can stay.  The garden changes daily in spring.  Take time to walk around and enjoy what changes each day.  If you do not have a garden to enjoy, come and visit me at Sandhill Gardens.

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