Most Frequent Gardening Questions

Year around Douglas County Master Gardeners are busy answering questions about gardening in our area. Beginning with the launch of our site, March 2008, some of our most frequent questions are being posted here. Check back regularly to see what your friends and neighbors are learning about gardening. There is a good chance you will have some of the same interests.

I have a beautiful amaryllis blooming right now. I heard that your can keep them from year to year. How can I do that?

Enjoy the plant thoroughly while it is in bloom. It doesn’t last long but it is truly spectacular and well worth preserving for years to come. After the plant finishes blooming cut off the flower stalk.

Maintain the plant with water and fertilizer throughout the summer. As the leaves die down they will feed the bulb. When the plant dies down in the late fall (stop watering to force it to do so if it doesn't by November) cut off the dead leaves. Then store the plant in a cool place like a heated garage (up to about 50 degrees), for example.

Late next winter, perhaps the first of February, bring the plant out into bright light and water. You should have another beautiful plant next year.

I want to start some of my own plants this year. When should I plant the seeds?

Just as you do not want to plant your garden all at the same time, neither do you want to start all of your seeds at the same time. There are two primary factors to consider. One is when they need to be planted in the garden and the other is how long it takes for them to germinate and grow to planting size.

First determine when you will want to plant your seedlings in the garden. This information should be on the seed packet. Cole crops like broccoli and cabbage need to be planted early, around the first of May. Tomatoes and peppers are tender and must be planted after the last frost, around the end of May. Memorial Day is the typical planting day in Douglas County but watch weather reports around that time when it comes to actual planting.

Second, look on the seed packet to see how long it takes to germinate and grow your seedlings. Again the broccoli and cabbage will take at least six to eight weeks. Since you want to have them ready by the first part of May you will want to plant them around the middle of March.

Plants vary widely in their needs so you need to check each one out individually. Snapdragons can be started twelve weeks before planting and can handle light frost like the cole crops so they can be planted as early as the first week in February! Zinnia needs to be planted after the last frost and only need two or three weeks to grow so they should be planted in early to middle May. Quite a difference.

There are no hard and fast rules. Weather is unpredictable in our area. Cauliflower may bolt and not do well if planted late. Other plants may freeze if put out too soon. But in general you can be quite flexible in your schedule. Don't worry too much about dates, just plant and enjoy.

This summer I would like to try composting. What kind of composter should I use?

While there are many composters available on the market, few of them meet the basic requirements for effective composting. To get efficient composting you need to have a compost pile about 4 feet wide and tall. Smaller composters will work but they take longer to process your compost.

There are many ways to construct a simple enclosure for your compost. One of the easiest is to simply secure a ring of fencing with ties to form a circle 4-5 feet in diameter.

It is also easy to stack concrete blocks. There is no need for mortar. Often these structures are only three sided for easy access.

Of course, a square bin of wood or a wood frame with wire fencing attached can also be made without much difficulty. Often more elaborate versions are constructed with two or three bins for easy rotation, turning and use of the compost.

Whether you buy or make one yourself, the important thing is to follow the basic rules for composting. Mix your materials so that you include green material like grass, brown material like dried leaves, and some soil or old compost to provide the bacteria needed. Then keep the pile moist and turn it regularly (stirring weekly is great) for quicker processing.

Compost is commonly referred to as “brown gold.” It is one of the best ways to improve your soil and well worth pursuing.

What can I do to improve the soil in my perennial bed so my plants will do better this year?

Most perennial flowers need good soil to flourish. A loose soil (sandy-loam) is generally best, one with good drainage and lots of organic material, can help your bed to produce an abundance of beautiful plants.

To get good drainage, especially in clay soils, dig in compost at least a foot deep and grade the bed with a slight slope to keep water from pooling. There are many types of ammendments that may be used effectively so check around to see what is available in your community. In rural areas, for example, composted manure is readily found while in urban areas peat moss and other materials are found in all garden centers.

It is a good idea to do a soil test to determine the need for fertilizers or to adjust the ph of the soil. You can get a kit from your local extension office.

While it is easier to work in a new area without plants you can dig in around your plants and slowly improve an existing bed. By working the soil where you are replacing or moving plants you can eventually have a much improved bed.

For more imformation check out the article, Amending Soils for Perennial Beds, on the University of Minnesota site.

Q: When can I expect the last frost in Douglas County? When will it be safe to plant my vegetables and flowers?

A: There is a lot of confusion over this question so it comes up year after year. Usually the question is asked in terms of the average last frost. The problem is, as any local resident knows, when it comes to the weather there really is no such thing as an average year in Minnesota!

When they ask the question, most people are expecting a specific date which they can use to guide their planting. A better approach is probably to keep a couple of dates generally in mind and apply an underlying principle to guide specific planning.

For Douglas County (Chandler Field in Alexandria) the 50% chance for a last freeze date is May 1st. The 90% chance for last freeze date comes on May 16th. Using the idea of “average ” really suggests a planting date that would lead to exposing plants to a freeze half the time. Obviously this is unacceptable. Waiting for no potential frost exposure is not practical either. So what to do?

The best idea is to use May 16th or so as a suggested time for you to take a look at the long range weather forcast and make an educated guess based on the projected trends at that time. There is a lot of variation from year to year, so there is no set date you can count on.

A related issue concerns the hardiness qualities of the plants. Using the frost date appropriately means applying it differently to different plants. Some plants like pansy, snapdragons, or broccoli like colder weather and can be planted around May 1st while plants like tomatoes or cucumbers are quite tender and must be planted only after any frost is unlikely. It all calls for good judgement and a willingness to accept occasional loses.

Why aren't my clematis blooming? Can/should I move or divide them?

A common question about clematis that comes up every summer has to do with blooming. It could be someone wondering why they are getting no blooms. Another issue has to do with moving or dividing this popular plant.

Clematis comes in three distinct types and are identified as belonging to one of three groups. If you know your variety try to look up the group in a reference of some kind. If you do not know the variety just experiment a little and you will be able to figure out what works based on the following information about these groups.

Group one blooms early, around May, and blooms on last year's growth. These should be pruned only after they finish blooming.

Group two, are mid-season bloomers and may rebloom in the fall. Flowers bloom on new wood from old buds. If pruned to the ground in the fall they will not have the early bloom but will bloom in the fall.

Group three blooms later in June and July. These bloom on new wood so you may prune at any time and many people cut back to the ground in the fall. To get flowering over most of the plant it is important to cut these back but it is preferable to only cut back to around 18 to 24 inches.

Clematis can be transplanted and divided but is susceptible to shock so should be treated carefully, moving as much rootball as possible. As with new plants, divisions will probably grow quite slowly the first year and somewhat so the next before becoming a thick, full plant.

Plants prefer lots of sun, at least six hours a day. At the same time their roots prefer cooler conditions. It is recommended to plant annuals or later growing perennials in front of clematis so that after the plant is growing well in the spring there will be shade for the lower parts of the plant.

How can I get rid of Creeping Charlie? How about using borax?

Creeping Charlie seems to be about as common a problem for some folks as mosquitoes. Often we hear about people wanting to try borax which is often recommended as a home remedy. But is this a good idea?

Scientific studies have shown in fact that borax is effective in killing this invasive weed. However, the active ingredient (boron) builds up over time and after multiple applications can kill grass and other plants as well.

For this reason, it should only be applied once each season and only twice altogether. After that use a standard broadleaf herbicide.

The University of Minnesota extension department has a brief on using borax for this purpose called USING BORAX TO CONTROL CREEPING CHARLIE which you can check out for further details.

What should I plant over my septic mound?

A fairly common question in our area concerns what should be planted over septic systems, in particular the mounds. There are a number of basic guidelines.

First, though, consider safety issues. It doesn't hurt to wear gloves when working in the soil. And needless to say, do not plant edible plants in this area. Remember that this is a potentially toxic area.

Don't plant trees or shrubs on the mound and trees should be at least 20 feet from the sides of the mound. Those with extensive root systems or those that seek water more than others such as willows should be even further away.

Select plants that have shallow root systems and those known for disliking wet soil. The best plants are those that will tolerate not being watered since it is best not to water or fertilize over the mound.

An excellent guide to planting over the septic mound is available online. Titled Landscaping Septic Systems, it includes more detailed information and a list of recommended flowers and grasses.