Thursday, November 30, 2017

Overwintering with Houseplants

T.W. Hardy

Initially, this blog post was going to focus on preparing your zone 7 and 7B gardens for the overwintering process. However, after performing some initial research, I learned that there has been an unimaginable amount of reputable information written and published on this topic. After the last cold hardy cultivars are removed and garden beds are put to rest for the season, gardeners have many options to get through the winter doldrums.

Figure 1. My home shelving unit for overwintering
Many commercial growers are developing new and exciting cultivars that are hardy for zone 6 and below. This is exciting for gardeners who prefer to keep their hands dirty through the late fall and winter seasons. Many gardeners take the winter months to peruse seed catalogs and plan their garden for the spring. However, for some this will simply not do. This brings us to our lush from the summer sun, houseplant cultivars. Fall and winter provide excellent opportunities to give our air-enriching plants some extra attention.

We can begin by gathering all those plants that may still be outside or in winter light-lacking and relocate them to locations throughout our homes and sun rooms. I chose to place all of my plants onto one shelving unit and provide supplemental light and moisture as needed, depending on plant health.

The following links provide sound overwintering tips:
And for those who like to stay warm indoors, preparing for next year’s growing season click here!

And for those who may desire to turn their homes into amateur laboratories, propagation provides another layer of houseplant enjoyment. There is ample information and articles available on the topic of propagation. A super easy plant to get started with is the "Spider plant" Chlorophytum comosum. I have seven plantlets growing from the specimen in the picture above. If I can propagate, I am confident that you can too!  
There are many gardening options available for us gardeners outside of tropical regions. Given the chance, our houseplants can provide us a nice distraction from “Old Man Winter” and the falling temperatures and precipitation that follows.

What houseplants are you growing? Have you propagated any lately? Please share your story in the comment section below. 

Thursday, November 16, 2017

Winter Storage of Tender Bulbs

Michele K. Koskinen

There are bulbs you leave in the ground to multiply and there are bulbs that must be stored for the winter. Those fanciful bulbs that grow in our spring and summer gardens like caladiums, elephant ears, gladiolus, canna and others are considered "tender bulbs". They are mostly tropical or warm growing plants that will not survive the cold northern winters.

Although they are not technically a "bulb" they are called that for convenience in many growing markets and this blog. Tender plants usually are from corms, tubers, roots, and rhizomes and must be stored for the winter as they are not winter hardy. Many, like a recent elephant ear purchase, are expensive so it is worth the effort to store them for the winter. Some will grow as houseplants if you have the right light and humidity in your home, it is worth considering.

Using my garden as a giant experiment from year to year, I am going to attempt to lift and save the tender bulbs in my containers. Canna, begonia and caladium are favorites on my deck. This year I also purchased a beautiful elephant ear. So time to research the how. The why is curiosity and getting started a little early and for those that have many tender bulbs, the cost of repurchasing every year also can become a reason to lift and store these bulbs.

Tender Bulbs should ideally be dug after the foliage has dried or a light frost has killed the foliage. 
The bulbs should not be allowed to freeze. They should then be "cured" before storing in the medium of choice. This year the foliage is just beginning to dry in my garden and a light frost is expected. I will be removing the bulbs and hope for the best in the curing process. Late November is upon us     

A few thing to remember:

          1. Storing these "bulbs" require two major requirements with other guidelines for specific plants. Cold and Dry is the name of the game and additionally lifting them right before or after the first frost is best for survival.

          2. Locate the bulb, and then using a fork inserted a few inches away gently pry the plant from the ground. Shake off the excess soil and allow the foliage and bulb to completey dry "cure" in a sheltered warm space.When digging up the bulb from the garden, dig gently so as not to damage the plant. Cuts on the bulbs before storage can bring in disease. 

          3. Make sure your bulbs are free of disease and fungus. Some resources recommend sprinkling an insecticide-fungicide on the bulbs.


To make your efforts more successful be mindful of temperature and storage materials. I only grow caladiums, canna and begonia so my information will only cover those plants. Follow the direction for storage for each individual plant cultivar, and use the links below to gain additional information for your project.

I have compiled and combined storing instructions for my specific plants.

    • Tuberous Begonia: Allow a frost to kill the tops, but do not allow the tubers to freeze. Lift and let tubers dry for one week, with about 5 inches of the foliage still in tact. Remove excess soil and foliage and store in peat moss or sawdust at 50 degrees F. Repot in early spring and keep warm, 68 - 75 degrees F. Move to a sunny spot when shoots appear. Keep evenly moist, but not wet. Plant outside after all danger of frost.
    • Caladium: Lift caladium plants before frost and allow them to dry in a warm spot. Cut back the foliage after it dies. Caldium bulbs don't like to be stored in cold temperatures. Keep at 50-60 degrees F. Pack loosely in peat moss. Repot up in early Spring, about 2 inches deep, knobby side up. Keep the soil moist and warm - 75 - 80 degres F. Move outdoors after all danger of frost.
    • Canna: Allow frost to kill the tops, but do not allow the rhizomes to freeze. Carefully lift the plants and cut off the dead tops . Hose off excess soil and allow to dry. Rhizomes can be wrapped in newspaper and stored in paper bags or cardboard boxes, at 45 to 50 degrees F. Very easy to overwinter. Cannas can be divided by hand. Break apart, insuring there are at least 3 eyes per division. Repot in early spring or plant directly in the garden once the temperatures remain above 70 

Videos that are helpful

Thursday, November 9, 2017

Questions from the Master Gardener Hort Line: Soil Testing, How Do You Get One and What Does It Mean?

by Pat Vance

Volunteers for the Philadelphia Master Gardener Hort Line have researched and answered some interesting questions. From time to time, we'd like to share some of those questions with you.

If you have a question about gardening, call us at 215 314 8711 or send an email to

There are more questions about soil testing than any other topic on the Hort Line. We get questions about how to have testing done as well as how to interpret the results.

Soil Test Kits

Getting a soil test is simple. Stop by any Penn State Extension office to pick up a kit. The address for the Philadelphia office is 675 Sansom Street, Philadelphia, PA and the phone number is (215) 471-2200. Call ahead to make sure someone will be there. The cost for a basic soil fertility test is $10. The kit consists of a sample bag, envelope, and form to be completed for your garden.

You can also print a pdf of the form, collect samples in your own plastic bag, and mail it in your own envelope. This is the ink to instructions on submitting samples:
To print the form, go to this url:
Open and print the pdf for “Individual Submission Form for Turf, Home Garden, Noncommercial Fruit, Flower, Woodlot, Christmas Trees and Landscape Plants.”
Include a check payable to “The Pennsylvania State University” along with your sample and completed form.

Complete the entire form as instructed.

Different plants have different nutritional requirements. Read the list on the second page of the form and choose the one that most closely describes your garden. Include the serial number from the bag if using a kit from the office. You can leave that space blank if you are using your own bag.

Any clean garden trowel will work to collect samples. Collect soil from the top 6 to 12 inches from 5 to 10 different spots in the garden to get a good representative sample. Remove plant debris and stones. Dry the soil on clean newspaper and then place it in your sample bag.

Be sure to label the bag with your name! And mail it to the address on the form.

If you have multiple beds, each with a different use, you may want to submit more than one sample, with a completed form and fee for each one.

Test Results

Your report will arrive in about 2 weeks. There will be a text box labeled “Soil Nutrient Levels” that will list pH as well as phosphorous, potassium, magnesium, and calcium levels. Look at the bar graph to see whether those levels are below optimum, optimum or above optimum. The lab will adjust this for your stated garden use. The actual values are listed in a box at the bottom of the page. If any item is not within the optimum range, there will be suggestions in the text box below.

Choosing a Fertilizer

To address nutrient levels, there will be a recommendation for fertilizer. Fertilizers available in garden centers will have an N-P-K value consisting of 3 numbers.  The first number is the total percentage of nitrogen (chemical symbol N), the second for phosphate (chemical formula P205), and the third for potassium (chemical formula K2O), usually in the form of potash.

For example, a fertilizer with an N-P-K value of 5-10-50 would consist of 5% nitrogen, 10% phosphate and 50% potassium. Fertilizers come in a variety of compositions of these chemicals. Typical combinations include: 5-10-50, 5-10-10, 10-10-10, 8-0-24, and 6-6-18. You can see that these fertilizers would give very different results in the garden. Your soil test will help you decide which of these would be best for your garden.

Keep in mind, though, that chemical fertilizers must be applied correctly. Too little will have minimal effect, and too much can harm rather than help. Follow directions on the package carefully.

Also, chemical fertilizers don’t have a long-term effect on the soil. The addition of compost and/or composted manure can make more permanent improvements. You can add bone meal to increase phosphates and kelp to increase potassium. These are available at garden centers. Compost will take longer to improve your soil than chemical fertilizers, so you may want to add fertilizer for a year or two while the compost does it’s magic.

pH Analysis

Another important part of your soil test is the pH analysis. The lists on the back of the submission form shows that plants vary widely in their optimum pH level. pH also affects how well your plants take up nutrients.

pH is a measure from 1 to 14 that indicates acidity or alkalinity. Low pH is acidic and high pH is alkaline or basic. Neutral pH is 7.0, where a substance is neither acid nor basic. pH units change by an order of 10, so a pH measurement of 6.0 is 10 times more acidic than a pH of 7.0.

Generally, vegetable gardens should be about pH 6.5, or a little lower than neutral. But some plants, such as blueberries like to grow in acidic soil, while clematis, for example, thrives in slightly alkaline soil. You will need to do a little research on your plants to be sure you are working toward the correct pH.

As with nutrients, there are actions you can take to change pH. Your soil report will recommend an amount of lime to increase the pH of your garden. The addition of sulfur will decrease pH but this has the same short-term effect as chemical fertilizers. Compost and other organic matter will decrease the pH of soil more gradually, but will be a more long-term fix.

More Information

For more information on building healthy soil, go to these links:

If you have any other questions and are not sure where to turn, ask the Hort Line! If we don't know the answer, we know someone who does!

Thursday, November 2, 2017

Lead Contamination: Is my Garden Soil Safe?

Questions from the Master Gardener Hort Line

Volunteers for the Philadelphia Master Gardener Hot Line have researched and answered some interesting questions.
From time to time, we'd like to share some of those questions with you.

If you have a question about gardening, call us at 215 314 8711 or send an email to

Lead Contamination: Is My Garden Soil Safe?

By Pat Vance

Beginning on June 18 of this year, the Philadelphia Inquirer ran a series of articles on residential land contaminated with lead. The first piece was titled “Toxic City: Tainted Soil” and written by Wendy Ruderman, Barbara Laker, and Dylan Pudell. Here is the link to the stories: ( These articles prompted a couple of questions to the Hort Line from people who wanted to know if their garden soil was safe.

Philadelphia’s Industrial Past

The Inquirer article points out that Philadelphia was home to many lead smelters in the past. The smelters are gone and there are now homes on many of the sites. The surface lead level in some of these areas is elevated. Additionally, when builders dig out foundations and dump the soil, the contaminated soil and dust can fill the air and settle on neighborhood yards.

The authors focused on Kensington, Fishtown and Port Richmond. They conducted a survey of that area and found that 75% of samples contained lead levels in excess of the EPA recommendation of 400 parts per million (ppm). Some were almost 25 times that level. Differing opinions are strongly held on the health significance of lead in soil, as opposed to the clear threat of paint chips and water, but it’s easy to understand why people are concerned. Lead poisoning is a serious health concern and children are especially vulnerable.
The Centers for Disease Control and Prevention publishes information on the health risks of lead
exposure at this site:

Previous Land Use in Your Area

One of the first steps you can take to calculate your garden’s risk is to review the site history for your property. This may help determine if there was industrial use in the area. Greater Philadelphia GeoHistory Resources provides interactive online maps of land use going back to the 17th century in at least some areas. The links for "Industrial Site Surveys" and "Land Use/Zoning/Development" have helpful information. I didn't find a way to search by address, but you can move the maps around and zoom in and out. The link is:

Also, the Inquirer article includes a map showing relative risk of lead contamination in the city. Here is the link:

Don’t Guess: Soil Test!

If you have any concerns, you can have your soil tested through Penn State University (PSU). The Penn State Extension Philadelphia Office is located at 675 Sansom St, Philadelphia, PA 19106, and the phone number is 215-471-2200.

Anna Herman, PSU Extension Master Gardener Coordinator, is collecting soil samples to be tested for free by the EPA. You can drop off a soil sample at the office. Several times a year, Anna will send them to be analyzed. The current estimated schedule is Nov 15, April 15, May 15 and July 15. Results typically return a couple of weeks after Anna delivers the samples.

If you want a test result in under two weeks, PSU Extension Agricultural Analysis Services Lab will test for heavy metals in soil samples if you check off “environmental soil testing” on their form. You can pick up a kit from the office. The cost is $27 for a test for lead. The price is $65 for a heavy metal panel that includes lead, copper, cadmium, nickel, chromium, and zinc. All of these metals plus arsenic, mercury, molybdenum and selenium is $160. (It is $10 if you only want soil fertility information)

It’s best to call ahead for instructions and to be sure someone will be there when you arrive.

The Inquirer article also listed several agencies that test soil. The link to that list is:

Interpreting Test Results

Penn State Extension has a publication that specifically discusses lead in residential soils. Here is the link:

This publication ranks lead levels as follows:

Soil Lead Level
(Total Sorbed Lead Test)
Level of Lead Contamination
mg/kg or ppm
Less than 150
None to very low
From 150 to 400
From 400 to 1,000
From 1,000 to 2,000
Greater than 2,000
Very high

The EPA puts the safe level at 400 ppm, even in areas where children play.

The health effects of lead in soil have not been studied as extensively as the effects of lead in paint and water, and there is some disagreement between agencies and experts.

Handling Lead Contamination in Your Garden

For the following sections, go to these links for more specific advice and information:

Growing Food Plants in Soil with Elevated Lead Levels

As a rule, plants do not take up lead very well. Fruiting plants such as tomatoes are the least likely, and leafy plants such as lettuce are the most likely to take up very small amounts when grown in contaminated soil.

However, the soil itself can be hazardous. Lead is harmful if ingested or inhaled. Lead can cling tightly to soil and produce grown in contaminated soil must be washed very thoroughly before eating, especially root crops. It is recommended to peel all root vegetables.

Gardeners also need to be careful not to bring soil into the home on gloves and clothing. Wash hands and exposed skin thoroughly.

Raised Beds

You can prevent plant contamination by using raised beds filled with uncontaminated soil. Cover the ground with plastic sheeting or some other barrier and then construct and fill the raised beds.

Non-Produce gardens

Covering the contaminated soil with sod will help lower your exposure. In beds for ornamental plants, shrubs, and trees, thick layers of uncontaminated soil and mulch is recommended.  Again, use more caution in areas that children will use.

Removing Lead-Contaminated Soil

It is possible to have the soil removed and replaced, but this is very costly and difficult, and is often prohibitive for the average homeowner.

New Contamination

As the Inquirer article points out, new construction may throw lead dust into the air, allowing it to settle on neighborhood yards. Roadways can also be sources of toxins that can end up in the soil. Try to reduce contact with soil within several feet of a busy road. Place low-maintenance ornamental plants close together and apply mulch. Plant your food gardens as far away from roads and construction as possible. Planting a windbreak between the road and the garden will help reduce the amount of wind-blown contaminants.

Ending on a positive note

For most of you, your soil is safe. As we always say: don’t guess, soil test! If you do find you have elevated lead levels, there are a number of steps you can take to assure your safety, and the safety of your families.

If you have any other questions and are not sure where to turn, ask the Hort Line! If we don't know the answer, we know someone who does!