« Back to all News

Archive for the ‘Ask A Master Gardener’ Category

What Flowers Do Not Need A Lot Of Sun?

April 13th, 2013

Hanging basket of flowers that only need part sun to growI have flower baskets that face east, so not much sun.  What do you recommend for a flower that does not need a lot of sun and has a vine or drape to it?  I’m in N.C.  Thanks. Pat J.

Answer: If you are limited on sun, generally less than 6 hours per day, there are some really nice colorful foliage plants available these days and they can be more dependable than flowers! There are several options in our Annuals section that would make great shade containers.

I garden with a lot of shade, and some of my favorites for sun/part share are: Abutilon; Bacopa especially the Snowtopia because it’s a nice trailing variety; any of the Begonia—the old standard Angel or Dragon Wing series are always great, but the newer Bonfire series are spectacular as well; and of course the Fuchsias are marvelous. One newer introduction, a variety of  Euphorbia, has tiny nonstop blooms that look a lot like Baby’s Breath and it makes a great filler plant or an entire basket on its own! Impatiens are a natural for the shade, and there is a new variety, Torenia, that will also tolerate some shade.

For pure leaf interest don’t forget about the Sweet Potato Vines. The horticulture industry has been tripping over itself to produce new and interesting varieties. I just love the new Sweet Caroline series. Coleus are perfect for brightening up shady areas, but some can get quite large, so you would want to check their mature size before considering them for a container. Plectranthus has some interesting leaf texture, as does Persian Shield. For tall, spiky interest use a Dracaena, and a shade area basket just wouldn’t be complete without a Fern or two.

Don’t be afraid to look at some of the Perennials, as well. There are many that make terrific options for containers. Start with Hosta,  Heuchera and its cousins, Heucherella, and Hedera. At the end of the season just put them into the ground to overwinter.

Happy shopping—and happy gardening!
Karen

How Should I Start Lemongrass

April 5th, 2013

Lemon Grass Plant Growig In A ContainerI would like several potted lemon grass plants for my patio. Should I start indoors now? How long will they take to grow 5-6 feet tall? Should I buy the stalks and start myself or just get the plants at a greenhouse? Thanks, Julie M.

Answer: You can start the lemongrass indoors from cuttings.  If you search our blog you will find several articles talking about this.  We do sell healthy starter plants, and these will be ready to go outside as soon as you’ve passed your last frost date. You are in Zone 5a, which means that date should be somewhere mid- to late May. If the plants are growing in pots they are not likely to reach their full size of six feet but should grow tall and full by the end of your growing season. Plants can be brought inside and overwintered as well, if you have a sunny, draft-free location.

Happy gardening!

Karen

Need Help Growing Lemongrass

February 28th, 2013

growing_lemongrassI’ve planted some lemongrass stalks that I bought and rooted in water. When they had a strong root system I planted them in a pot and put them on a southwest window sill. I’ve tried to maintain moisture and fertilized, but unfortunately not only have they not grown but they are slowly withering away. I hope you can help me figure out what I can do to keep them alive and hopefully get them to grow into a decent plant. I live in the south of Spain where the climate is warm and dry most of the year, but I have to keep delicate plants indoors in winter as we are at the foot of the Sierra Nevada mountains and get frosts. Thanks, Diane

Answer: It’s always difficult to fully diagnose the exact cause of plant failure, but here are some suggestions to try again.

I see about a 50/50 rate of suggestion as to starting lemongrass in water or soil. Most who recommend water rooting do suggest to transplant directly to soil. However, the cell structure of water roots is different from that of soil roots, so it’s imperative to keep the soil generously moist in the early days of transplanting. You can even cover the plant with a plastic bag to seal in the humidity. Another method to move the plant to soil is to daily add soil to the water to allow the roots to transition in cell structure.

You might also just try using soil to start the lemon grass. Just make sure it’s well draining. You will want to cover the pots to keep the moisture in.

Keeping the plant in a warm sunny spot is important, as well. If there is a draft from the window, you might try moving it to a warmer spot and make sure it’s getting as much full sun as possible.

Do not fertilize the starts. Let them show active growth before applying any type of fertilizer. Most plants don’t need a lot of fertilizer except when blooming or fruiting, to help boost that process.

Give it another try, and maybe test both methods and see which works best for your conditons.

Happy gardening,

Karen

Frost Protection Blankets and Wind Chill

February 21st, 2013

Dear Master Gardener, Can you tell me how wind chill affects the plants under a frost blanket? For instance, if I am using a 24-degree frost blanket for protection and the temp is 28, however we are having winds at 25 mph, what effect does that have under the blanket? Or how much temperature protection will my plants lose due to windchill? Thank you so much, Denise

Frost Blanket covering plants

Answer: Denise, That’s an interesting question. Frost blankets will effectively “zone up” your area one zone. It’s like a coat for your plants. However in the case of wind chill, only humans are affected by this. Wind chill estimates the amount of heat loss from warm-blooded creatures as the wind passes over exposed areas of the body. Plants do not generate heat, so essentially they are not directly affected by wind, and if under cover they would not be affected by the wind.

What can be more detrimental to your plants is the dew point. This is the temperature where air reaches water saturation. There are several scientific methods of calculating this and the numerous effects it has on vegetation. Water vapor helps to slow the temperature fall. With a high dew point, radiant heat losses are slowed, but if the dew point is low, the temps may fall rapidly. Think of how fog in an evening will make it warmer.

You can add some forms of mild heat under the frost blankets, like Christmas lights or milk jugs of water that have absorbed the sun during the day.

Hope that helps—and happy gardening.

Karen

Which Onions Should I Plant?

December 11th, 2012

Short Day Variety Onion PlantsI am trying to figure out which type of onion to plant. We are in Zone 7, which seems to be in between long day and short day. During mid-May and all of June and July the daylight hours are over 14 which seems to be long day. Any ideas? James K.

Answer: It seems for your area and planting time your best choice is the short-day variety requiring only 10-12 hours of daylight. Some overlap into the intermediate variety can work, but if you are just getting into growing them, start with the short-day. Don’t forget to add the ammonium sulphate dressing about a month after planting.

Great Gardening~

Karen

Will This Keep My Plants Alive During The Winter?

November 15th, 2012

I have a metal frame left standing on my south deck which is 10′ X 10′. If I wrapped and covered this with thick plastic sheeting, would it keep my plants alive through the winter? Thank you, Cecile.

Answer: Well, this will help protect some plants during your winter season, but you will need to know the plants’ Hardiness Zone. Your location is Zone 8a. Typically, adding one layer of protection, like a heavy plastic sheeting or row cover fabric, will add one Zone in protection, so theoretically inside would be Zone 9, and you can add an additional cover or protection inside for an additional Zone. You begin to get a significantly diminished light source with the second layer, so be selective on what plants you are protecting. Make sure that the plastic and structure are securely fastened down, as this will be highly susceptible to high winds and could easily blow apart, exposing the plants to weather they are unaccustomed to.  A UL-approved heater for wet locations could also be added. Just make sure it’s in a properly grounded outlet. I’ve also used a remote thermometer so I can keep track of night temps in my temporary greenhouse, and you want to make sure that there is a way to vent it on sunny days, as the temps can climb rapidly.

Do some reading on greenhouses and cold frames to see how they are best secured to a structure. Also make sure to research the Zone of the plants you are trying to overwinter to see what they like. Some tropicals can be put into dormancy and overwintered in a basement or garage that stays above 45 degrees, much easier than worrying about them outside!

Good luck with your cold frame.

Karen

Why Are My Pole Beans Not Setting Blossoms?

August 20th, 2012

IPole beans growing up a pole in the garden have planted Blue Lake Pole Beans. The site gets a lot of sun and I water on the base every day. I have beautiful plants but no blossums. Another type of pole bean, Burpee I think, has produced blossoms in the same vacinity. It has been almost two months and the plants themselves are very robust but no indication of flowering or beans. Please advise.   Bruce S.

Answer: I cannot give you a definitive answer as to why one variety did well and one did not, but I can give you some possible reasons.

In general, Blue Lake Pole beans need the following conditions:

First, they do not like to have too much nitrogen in the soil. The nitrogen makes them nice and leafy but inhibits blossom production. Since beans go thru a process of “nitrogen fixation” where they produce nitrogen in their root systems if the soil is already nitrogen rich from compost, then it could be the cause of no blooms. Test your soil first to determine nutrient levels. Heavy, clay soils will hold a lot more nitrogen than sandy soils where the nutrients tend to leach out.

Second, is the weather. Beans like the temps in the 70- to 80-degree range and if the temps are consistently over 85, then the blossoms will not develop. Hot dry winds will also aggravate the situation. Temperatures under 70 will cause the plant to not even attempt flowering. East Coast temps have been pretty high, so this could be a problem. It’s possible the other variety is more tolerant of such conditions.

Another thing to consider is fluctuations in soil moisture. The Midwest is experiencing a severe drought, so if you are having the same conditions, then that combined with the heat could be causing much stress on the plant. Blossom drop always occurs under stress conditions.

Also monitor for signs of any kind of disease.

Check the ripen time: Blue Lakes are typically around 60 days to harvest. They could be waiting for some cooler weather, as well.

I hope that gives you some ideas of things to look for. Remember, you could start some new plants and maybe get a late harvest out of them, when hopefully the weather is more cooperative for growing and fruit production.

Good luck with your garden,

Karen

Why Are My Tomato Blossoms Falling Off?

August 1st, 2012

tomato plant with blossoms falling offI have a large (6 ft.) tomato plant, but a number of the blossoms fell off before even becoming a tomato.What is the cause and treatment? Dale H.

Answer: Since you didn’t list any other conditions, I am assuming they are getting full sun and are not suffering from any other tomato specific diseases.

Blossom drop is a fairly common problem with tomatoes, but there is no one thing that’s responsible. Here are some possible causes to help you diagnose the situation.

Temperature is the biggest factor. Tomatoes prefer a daytime high temperature above 85 degrees, and at night the temps should be between 55 and 70. There are different varieties that are more heat-tolerant: look for the phrase “heat set” on the tag or description. High night temps are troublesome for tomatoes because they don’t get to rest; if you’re having consistent high daytime and nighttime temperatures, the plant will abort setting fruit and just focus on staying alive.

Pollination is important.  If you are not seeing bees around the plant, you might have to hand pollinate or plant other blooming annuals around the plants that will attract bees and other pollinators.

Don’t over-fertilize. Many people think they should feed their plants weekly, which will ensure a nice green plant but usually few blooms or fruits. A well-tilled soil with good organic matter (compost) with a little balanced fertilizer when you plant, then a light application of balanced fertilizer when you begin to see fruit set, is all the plant needs.

Humidity outside the ideal range of 40-70% will also interrupt pollination. If humidity is too low you can water the foliage during the day; if it’s too high in your area, you’ll need to look for varieties that have been developed for high humidity climates.

Watering consistently is another important factor. Half a gallon every morning and night is just what they need.

Watch for fungal and other visible diseases prevalent in tomatoes that can inhibit blossom development.

Good luck with your tomatoes. I hope they begin to develop lots of juicy fruits.

Karen
Master Gardener

Why Are My Tomato Leaves Turning Yellow?

July 17th, 2012

Hello, I live in a condo and have gardened my front yard for 10 years. I have 9 tomato plants. Each spring I dig a new hole, discard the earth, and fill with enriched soil. 1 of 9 has gone bad. Yellowing of leaves up the entire plant, lots of bumps on the stem, and fuzz or powder on plant. Any ideas?  Thank you, Jim

Answer: Well there are a number of possible reasons for the such symptoms. First I would suggest that you not discard the previous soil but simply augment it yearly with compost. By using highly enriched soil, you are causing the roots of the tomato plant to not want to expand past the good stuff, thus actually weakening it, especially with the heat and drought conditions of this summer. It’s always good to add compost to the soil in the spring, but don’t over-enrich it.  Too much of a good thing isn’t better. This overly rich soil could also be holding too much moisture, which is not good for the plant and could be introducing other diseases.

Another common problem with tomatoes is the susceptibility to several fungus issues, especially verticillium wilt or fusarium wilt. There are new plant varieties that have been developed to be less susceptible to these problems.  Check your variety’s specs, as these characteristics are included on the label. Do some research online for specific signs and treatments; they differ slightly, so you need to know which one you have. Both will suggest crop rotation, because they are soil-borne pathogens. If you are in a small lot and cannot move them, then you might consider using pots, or a raised bed. Also check the pH of your soil: tomatoes want a nice neutral soil, 6.5 -7.0, and in PA you might be too acidic.

The bumps are normal on the lower portion of the stems. They are called stem primordia and are just areas that could develop into roots, if needed. When they develop higher on the stem, it could be caused by excess moisture in the soil or too-high humidity levels. While they are not a problem, if your plants are developing these in the top portions, then it’s a signal that they are staying too wet. You might want to use a soil moisture meter and check before watering.

The last couple of years have also presented significant issues with unusual temperatures and water, or lack thereof, which are outside the norm for most home vegetable gardeners.

Best of luck. Karen

When Should I Order My Fall Vegetable Plants?

July 11th, 2012

broccoli plant growing in the gardenMy broccoli was fabulous and I want to plant broccoli and cauliflower again for the fall.  If I order vegetables now, will you ship at the appropriate time for transplants in Zone 5? Thanks, Ann-Marie

Answer: Sorry, Ann-Marie, but whatever you order now will ship now.  You need to know when your first frost/freeze date is in the fall and then count backwards however many days the particular plant needs to mature. I would also add an extra 10 days.

So if Avenger Broccoli takes 50-60 days, I would plant it 60-70 days before that first frost date.  Also add an allowance for the number of shipping days to determine the right time to order.  This would be the rule of thumb for all our vegetable plants.

Here is a map for fall frost dates:  http://www.ncdc.noaa.gov/img/climate/freezefrost/Fall28F_hires.jpg

Hope this helps. GHS