| Holtkamp Greenhouses, Inc. benefits from a worldwide fascination with the African violet. Its name notwithstanding, the African Violet Society of America lists 16 affiliates including regional clubs in Europe (including Russia, the Ukraine, and Romania), Australia and New Zealand, the Far East, Africa and the Near East, Canada, and Mexico and South America! Wow, now that’s a lot of potted plants.
Part of the enduring appeal of the African violet is its link to family history. It’s likely that your grandmother, like my grandmother, grew African violets. It’s nice to “grow” a family tradition (if not the actual plant itself; they can live for quite a long time). Not only is it a beautiful flowering plant, but an African violet produces lots of color for relatively little effort. It’s one of the few houseplants that blooms—well—in average household light conditions. African violets are also amazingly cost-efficient; a blooming 4-inch pot can sell for less than $3, making them an affordable “introduction” to consumers for indoor plant culture.
Here are the basics of growing African violets, according to Holtkamp Greenhouses:
Light: Place where the plant receives moderate to bright, indirect indoor light.
Water: Watering is the biggest “issue” of African violet care. Bear these tips in mind: keep soil moist to dry; let the potting soil dry out around the roots; water from the bottom with room temperature water, and after 30 minutes discard the water from the saucer; and avoid getting water on the leaves.
Feeding: Feed according to the directions of a fertilizer formulated specifically for African violets. (Fertilizer is often a liquid added during watering.)
Grooming: Deadhead (pinch off) old blooms to encourage reblooming.
Location: Avoid placing African violets near a vent, fans, or doors to prevent them from being blasted by cold air.
Soil: Use a good quality potting soil, not outside soil. Its pH level should be between 5.8 and 6.2.
Because of its amazing growth, Holtkamp Greenhouses is reportedly adding more than 70,000 square feet of greenhouse space to accommodate what appears to be a still-growing market. In addition to African violets, Holtkamp breeds and sells other flowering houseplants such as orchids, miniature poinsettias, and begonias. |
 Everything’s coming up roses—well, actually African violets—for Holtkamp Greenhouses, Inc. From one square meter (10.76 square feet) of greenhouse space dedicated to growing African violets in the 1930s to one-half million square feet of greenhouse space today, Holtkamp, now the world’s largest grower of African violets, has grown explosively recently.
The parent company was founded in 1904 by Martin Dorrenbach in Germany, then passed to his son-in-law Hermann Holtkamp, Sr., a horticulturalist who started breeding African violets specifically in the 1930s. Hermann Holtkamp named his first cultivar ‘Saint Martin’ in honor of his father-in-law, Martin Dorrenbach.
The company moved part of its operations to the United States in the 1977, where it continued to grow. (There are other divisions of the company as well, located in Germany and in Spain.) Now, control of the American company has been passed to Reinhold Holtkamp, Jr., who operates this multi-million dollar business with his family. Hidden in an unassuming residential neighborhood in Nashville, Tennessee, Holtkamp Greenhouses is the primary supplier of African violets to major retailers such as The Home Depot and Kroger.
Sold under the trademarked Optimara name, the plants are superior hybrids of the original Saintpaulia genus discovered in Tanzania in the late nineteenth century.
The company cultivates more than 100 varieties, in colors ranging from blue, purple, pink, white, and bicolors to bicolors edged in silver or white. The cultivar names are very fun, and include ‘Jitterbug’ (red with a white edge), ‘Miyako’ (purple with a white edge), ‘Aruba’ (light blue with a white edge, ‘Picasso’ (pink with splashes of purple), and many others. They are exquisite.
Hermann Holtkamp’s breeding efforts resulted in the first non-shedding African violet in the 1960s. Before his discovery, African violets were notoriously “tricky” about dropping their flowers if disturbed. It not only did not drop its flowers, but it could withstand the colder temperatures found in refrigerated shipping transportation trucks. That was revolutionary for the industry. |
| We want to thank you for making 2010 a fantastic year for
Private Garden
May you and your family have a safe, enjoyable holiday season and
a
Happy New Year!
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Although plants don’t breathe as we do, they do need oxygen and air circulation. Many people aren’t aware that roots need oxygen; it’s probably the most overlooked “nutrient” that plants require. That’s the reason that compacted or poorly draining soil is so bad for plants; their roots cannot “breathe” in them. Amending soils so that air spaces exist among the soil particles allows roots to breathe, which is why amendments are recommended for virtually all soil types.
In a greenhouse setting, most plants will be growing in a potting medium, so it’s unlikely that compacted soil around plant roots will be a concern. But, plants growing in greenhouses in winter do need air circulation in a big way. Plants also breathe by a process called respiration through their leaves that exchanges oxygen and carbon dioxide.
Because a greenhouse is an enclosed environment, you’re essentially creating a microclimate. The process of respiration can produce quite a bit of water vapor, or condensation, and too much in an enclosed microclimate is not good for plants. High humidity and condensation can lead to disease problems. Circulating air helps maintain both uniform humidity levels and temperature.
It’s not difficult to increase air circulation in a greenhouse. Here are some tips:
- If you’re using benches, you can install mesh screen or slatted-type benches to increase airflow around the plants.
- If you don’t have access to mesh or slatted benches, you can space plants farther apart from one another so there is more airflow around them.
- One of the obvious solutions is to add a fan (or two) to your greenhouse. A fan will also move warmer air from the ceiling throughout the greenhouse. Ideally, install two fans on diagonal corners of the greenhouse, and position the airflow so you get an “oval” pattern, if possible. The fans should be about 2 to 3 feet above the tops of the your plants.
- If you’re using a heater in your greenhouse for the winter, check to see if the fan unit can run continuously on its own on/off switch, separate from a thermostatically-controlled heating element.
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Greenhouse growing, while truly great for many reasons, is not without its fly in the ointment, so to speak. Because it’s a closed environment that means  that natural predators are prevented from entering (unless deliberately introduced). So populations of pests can explode. There are several pests that are relatively common in greenhouses, including: aphids, fungus gnats, whiteflies, and spider mites.
Recognizing what you have is the first step toward control and eradication. This step is critical, because you don’t want to treat pest problems indiscriminately with chemicals (or even biological controls), especially if you are growing edibles. Even though the word “pesticide” implies that it works on everything, the truth is that virtually all pesticides are very specific regarding what they target.
Aphids: Aphids are soft-bodied, sap-sucking insects. Their pear-shaped bodies can come in a range of colors (green, orange, red, yellow). Aphids not only suck plant juices, weakening plants, but they excrete a substance called “honeydew” that can cause a condition called sooty mold. Treat by releasing lacewings or ladybugs (also called lady beetles). Insecticidal soap also works well, as does spraying with water and pruning off affected stems.
Fungus gnats: Fungus gnats are tiny, blackish to grey flies. They don’t live very long, but they reproduce massively! Fungus gnats can transmit plant viruses, such as Fusarium wilt, and Botrytis. These are not good. Two organic controls are Bt (Bacillus thuringiensis) or Neem oil (as soil drenches). Don’t overwater.
Whiteflies: Adult whiteflies look like tiny white moths. They also breed like crazy. The juveniles suck plant juices, like aphids. Also like aphids, whiteflies excrete honeydew, which promotes sooty mold. You can handpick heavily infested leaves (and throw them in the trash) or release lacewings or ladybugs.
Spider mites: Important: spider mites are mites—not insects. These tiny creatures, hard to see with the naked eye, live on the undersides of leaves. They feed on leaves, bruising them so the leaves look speckled. The two-spotted spider mite is the one that most often infests greenhouses. Treat with insecticidal soap being particularly careful to get the undersides of leaves. There are actually predatory mites that feed on spider mites.
Yellow sticky cards can also catch many insects, especially flying ones. Aphids, whiteflies, and fungus gnats are attracted by its yellow color and they get stuck on the sticky surface. |
|  Imagine showing up for dinner or a party bearing a beautiful, blooming flower. Amaryllis(Hippeastrum species) are very popular holiday gifts because of their ease of growingand vivid choice of colors of salmon, rose, pink, white, apricot, bicolors, and a colorpattern called picotee (often edged in white though it can be another color). Their large,trumpet-shaped flowers are borne on sturdy stalks ranging from 1 to 2 feet tall. It’s a spectacular centerpiece!
But while most people who are gifted with amaryllis receive a potted bulb kit, you cangrow this perfect hostess gift right in your greenhouse. It takes about 6-8 weeks for ablooming plant, but you can begin the process and give a started amaryllis. It’s still agreat gift. Here’s how to do it:
Select the largest, firmest bulb you can find. You should be able to locate bulbs only at garden centers, but if you must, you can purchase a kit. The bulbs
shouldn’t show any signs of mold or decay.
- Find a pot that’s about 1 or 2 inches larger in diameter than the bulb itself that’salso deep, for good root development. You’ll think it’s too small, but amaryllislike things snug. (This is a good time to raid your supply of containers that you’vepicked up over the summer at yard sales. Yard sales are fantastic sources forthings like pots.)
- Fill the container about two-thirds full of well-draining potting soil. Set the bulb like a duck sitting on the water—half of it in the potting medium and half out. Firm the potting soil around the bulb and water.
- Find the warmest spot in your greenhouse that has bright, but indirect light, and put the potted bulb there. Periodically give the pot a turn so the bulb (and laterthe emerging stalk) receive equal amounts of light on all sides. If needed, you canstake them but be careful to avoid piercing the bulb.
- Keep the potting soil moist but not wet. Once you see signs of growth, fertilize (and keep feeding to support those massive blooms).
Amaryllis is the gift that keeps on giving because a plant will continue to bloom,especially once it is potbound. Your thoughtfulness will be remembered long after thedinner or party.
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 How many times have you purchased salad greens, only to have them go “bad” in the refrigerator? (I always imagine them like Wild West gunslingers, with little pistols on their lettuce hips.) They are often so far gone by the time you rediscover them that they are a gooey mess. Not only is that gross but it’s wasteful to buy food that you simply throw away. You might as well be tossing dollar bills into the trash.
The solution? Grow a salad a day, the greenhouse way. When you have a greenhouse, you can grow a continuous supply of fresh, nutritious salad greens and never throw any of it away. You can even grow lettuces year-round in cold climates if you have a basic heat source in your greenhouse to maintain a cool temperature.
Lettuce and other salad greens leaves get larger as they mature but don’t go “bad.” You just snip off the outer leaves as you need them for your salad. How great is that? Some great varieties for greenhouse growing include leaf lettuces, Bibb lettuces (also called Boston or butter lettuce), and Romaine. Mesclun (literally meaning “mixed”) refers to greens, herbs, and lettuces, with types of leaf lettuce a heavy component; it’s another great type of lettuce that becomes accessible for year-round growing with a greenhouse.
But what’s a salad without dressing? It’s just lettuce, that’s what it is! Here’s a quick and easy recipe for an herbed buttermilk dressing. The Dijon mustard adds a great depth of flavor. You can also add some mayonnaise if you want a thicker dressing.
Herbed Buttermilk Dressing
½ cup buttermilk (shake it up really well before measuring)
½ cup sour cream or Greek-style yogurt
¼ cup finely chopped flat-leaf Italian parsley
3 scallions, white and green parts chopped
1 garlic clove, finely chopped or minced (use 2 cloves if you’re bold)
1 tablespoon lemon juice, preferably freshly squeezed
1 ½ to 2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
1 tablespoon Dijon mustard, optional
¾ cup good-quality mayonnaise, optional
Combine the buttermilk, sour cream or yogurt, parsley, green onion, garlic, lemon juice, salt and pepper in a nonmetal bowl. If you like, add the Dijon mustard and the mayonnaise. Whisk until well blended. Then cover and refrigerate for about an hour to let the flavors blend. Yummy! |
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From time to time, we're going to bring you virtual tours of some of the most beautiful estate and commercial greenhouses and glass houses. Here's a tour of the Belmot Mansion Greenhouses.
If you’re traveling through Nashville, Tennessee, it’s worth a trip to visit historic Belmont Mansion, the home of Adelicia Hayes Acklen Franklin Cheatham, a real-life southern belle with gumption. Born in 1817 into a well-to-do Nashville family, Adelicia married a man several years her senior who left her a wealthy widow upon his death. By the time of her death in 1887, Adelicia Acklen was ranked as one of the wealthiest women in America. When she married her second husband, Joseph Acklen, in 1849 they embarked upon building a magnificent Italianate-style home named “Belle Monte”—“beautiful view” in French. This massive 20,000 square foot home stands today as one of the finest house museums in the country.
Belmont Mansion was a marvel for its time. Set amid elaborate gardens, the estate contained a bear house, a private zoo, a bowling alley, an art gallery, a water tower, and a 200-foot-long greenhouse that provided both fresh edibles (grapes) and overwintered an extensive collection of landscape and potted plants for the estate gardens. According to mansion director Mark Brown, among the plants listed in documented accounts of the greenhouse are: cacti, camellias, night-blooming cereus, water lilies, and fuschias. It is likely that the greenhouses overwintered indoor potted plants as well, as Belmont was built primarily to serve as a summer residence only.
The greenhouses consisted of four connected sections, built entirely of glass, and heated by a basement furnace. They featured cast-iron grates that matched the cast-iron gazebos on the grounds (which are still standing). The greenhouses and grounds were maintained by a succession of full-time European gardeners, who lived in the Italianate-style gardener’s cottage behind the greenhouses. The still-standing water tower provided running water both for the greenhouses and for the Mansion. Interestingly, the original structures stood until the 1920s, when the precursor of Belmont University dismantled them to make way for expansion.
Learn more about the Belmont Mansion by visiting their website, here. |
Private Garden is Building a Victorian Glasshouse at the Bellagio in Las Vegas ... RIGHT NOW!
Written by Jennifer Sackrider
Monday, 09 August 2010 18:22
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If you are in Las Vegas for the Home and Garden Showplace Show, visiting, or just live there, please come by the Bellagio Hotel and Resort to see Private Garden building a Victorian Glasshouse in their Garden. We will be there for the next 36 hours building the Victorian Glasshouse. Please keep checking back for photos through out the process.
The Bellagio theme for their garden this fall is the Whimsical Fall Show. The Private Garden Victorian Glasshouse will have Orchids and made to look rustic.
Private Garden's Victorian Glasshouse will be on display at the Bellagio for the next few months. When the Bellagio changes their display, Private Garden will be there to dismantle the unit and then install it at a local school as a donation.
Keep checking back to Private Garden for our future projects with the Bellagio Hotel & Resort!!
 
 
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Chelsea Flower Show Special
Written by Jennifer Sackrider
Monday, 09 August 2010 18:21
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| On May 25, 2010 the annual RHS Chelsea Flower Show opened in Chelsea, London, UK.
The RHS Chelsea Flower show is the largest, traditional flower show in the world and has been around for 148 years. Designs from Chelsea become instant gardening trends, spreading rapidly around the world. Private Garden’s manufacturer, Alitex LTD, will be exhibiting at the RHS Chelsea Flower Show, so as a Private Garden customer, you’re already in the forefront of gardening trends and technology.
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Have you noticed the best things from Tiffany’s come in the smallest boxes? Eventhough a life-sized greenhouse is definitely on your “I’ve Been Good” list, the Wardian case, the direct predecessor of the terrarium, is a miniature greenhouse that fits inside your home.
