Articles

What Is The Best Potting Mix for Potted Shrubs?

“I will be planting shrubs in containers. Which potting mix between Fafard and Black Gold would be the best choice and longest lasting? I would prefer something more permanent so as to not have to change out the potting mix every few years. I live in zone 7. Thank you for your response.” Question from Mel of Atlanta, Georgia

Answer: When recommending the best soil for potted shrubs that will be there for the long term, I always suggest filling the pots with 1/3 quality topsoil or ground soil and 2/3 quality potting mix. Mix the two evenly before filling the pots. I like to add ground soil because potting mixes tend to acidify over time, and ground soil, which is primarily inorganic, helps buffer the acidification process, and it will not break down and shrink over time. You might also consider adding some other ingredients, such as sand or pebble, depending on the shrubs grown. Finally, be sure to refresh the pot with new potting mix seasonally. The addition of dolomitic lime can also reduce acidification.

With that said, I would choose the following mixes for long-term potted shrubs.

Feed your shrubs seasonally in the spring with a slow-release fertilizer. It is also important to note that potted shrubs are most apt to survive winter if they are at least two zones hardier than your zone because they are more exposed.

All the best,

Jessie Keith

Black Gold Horticulturist

What Are the Best Container-Garden Plants for Shade?

Impatiens are classic potted flowers for shade!

“I’m in a complex where we can only plant in containers outside…and there’s a lot of shade to complicate matters…any idea for some plants that would do well contained without a lot of sun?  Thank you…also someone told me the ivy I did plant in a pot can be brought inside for a houseplant when it gets too cold outside true or not?” Question from Kim of Orangeburg, New York

Answer: There are lots and lots of wonderful annuals that thrive in shady locations. The perennial vine, English Ivy (Hedera helix), can grow in pots inside or out, and it will take shade, but there are many better options for shade containers. Here are some of my favorite shade-loving annual garden flowers for summer potted gardens.

Annuals for Shady Container Gardens

Begonias: You can’t go wrong with begonias, as long as you provide them with good moisture, especially through the hottest summer days. Two showy high performers are Bossa Nova® Red  Begonia and Illumination® Golden Picotee tuberous begonia. Classic wax begonias that you can purchase in flats at every garden center are also inexpensive and excellent.

Bush Violets (Browallia hybrids.): These annuals are nonstop summer flowers. Try the true-blue Endless Illumination Bush Violet.

Coleus (Solenostemon hybrids): There are hundreds of different types of coleus available with the most colorful, beautiful foliage imaginable. Click here for a wonderful coleus online nursery! (Click here to learn how to take coleus cuttings to generate new plants for free!)

Classic Impatiens (Impatiens walleriana): Pick up a flat of colorful impatiens at your favorite garden center, and plant them in shady pots for summer-long color. (Impatiens are also easy to start from seed! Click here to learn more.)

New Guinea Impatiens (Impatiens hybrids): These impatiens are generally taller and tolerant of a little more sun than classic impatiens. the tangerine-orange Infinity® Orange is especially pretty as is the crimson-pink and pale pink Infinity® Blushing Crimson.

Torenia (Torenia hybrids): You cannot go wrong with any of the spreading torenia in the Summer Wave Series. They spread and bloom all summer long. Summer Wave® Large Blue is really lovely.

For more ideas, try the Proven Winners Container Garden Recipe search. It is a great resource for gardeners just learning how to create spectacular potted gardens. Just be sure to choose “Full Shade or Part Shade” for the sun-exposure dropdown. I also recommend clicking here to learn more about growing perennials in containers.

Happy gardening!

Jessie Keith

Black Gold Horticulturist

What Black Gold Potting Soil is Best for Potted Tomatoes?

“Hi — I just transplanted tomato starts from the bathtub to larger containers and used Black Gold All Purpose for much of it.  I had one bag of All Purpose and one of Natural, Organic.  I noticed that the All Purpose has more fertilizer in it.  The Natural Organic has less, but it is natural and organic.  Still, I’m thinking I should generally use the All Purpose — because it seems like the transplanted tomatoes have really benefited from the fertilizer in it (more than they might benefit from what’s in the Natural/Organic).  What’s your perspective?  I don’t think it’s my imagination that the tomato starts to look quite a bit better after transplanting into the All Purpose.  I’m just not sure if they’ll do roughly equally well in the Natural and Organic Potting Soil.  There’s less fertilizer.  I don’t see the differences clearly yet with my starts for reasons that I won’t bore you with.  Please advise.  :-)” Question from Steve of Bow, Washington

Answer: The Black Gold All Purpose Potting Mix contains supplemental fertilizer to feed plants for up to six months, while Black Gold Natural & Organic Potting Soil contains no added fertilizer. That’s why you saw better growth in the seedlings planted in the All Purpose, but both are good choices for potted vegetable growing. I would also add that tomatoes are very heavy feeders, so I recommend adding fertilizer that is specially formulated for tomatoes anyway. There are loads of fertilizer options for tomatoes on the market.

We have several other soils that are ideal for tomato growing because they hold extra water and are OMRI Listed for organic gardening. These are Black Gold® Natural & Organic Flower and Vegetable Soil, which is very porous and fertile, and Black Gold Natural & Organic Ultra Coir, which holds extra water for thirsty tomatoes. From there, I recommend that you watch the video below with great tips for how to successfully grow tomatoes in containers.

Happy tomato growing!

Jessie Keith

Black Gold Horticulturist

How Do I Protect My Bulb Pots From Rot?

“I tried planting bulbs (crocus, daffodils, tulips, and iris) in pots this year. They were well mulched and gathered in a warmer area of the garden near the house. Nothing came up! After investigating, it appears they became too wet and froze. The pots have great drainage. Any suggestions for next year will be greatly appreciated. Thank you!” Question from Jane of Bloomington, Illinois

Answer: Bulbs are adapted somewhat to freezing and thawing, but if they get too wet, they are prone to rotting, especially when temperatures are mild in fall and spring. There are several things that you can do to protect them from excess winter water. The easiest way is to simply store the pots under a patio or protective eave. You can also add more amendments, like Black Gold Perlite, to encourage faster drainage, but overhead cover gives one a bit more control. On the flip side, there is always a chance that they may become too dry under cover, so intermittent watering from fall to spring is recommended.

It is also advisable to protect your tulip and crocus bulbs/corms from rodents that enjoy munching on them in the winter months when food is scarce. Applying some repellent granules around the bulbs at planting time will help. From there, I recommend that you read Mike Darcy’s excellent article about creating layered bulb pots in the fall (click here to read).

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Spring Salad Pots For Quick, Easy, Fresh Eating

Last year I experimented with salad pots with great results. This shows some of the pots just after planting. They contain mixed lettuce, bok choi, and beets. Another pot contained six large Romaine lettuce plants.

My first spring salad pots were grown in large, inexpensive plastic containers that I bought from the garden center. I filled them with some Black Gold Natural & Organic Potting Mix and added a little fertilizer. They performed so well that I couldn’t believe it. Just a few pots provided delicious salads through spring, so this year I decided to redo this year’s salad containers with a little more flair.

I took it up a notch by creating suites of well-paired greens and herbs for custom-made salad containers–one with an Asian theme, another French, and the last for the Italian palate. Large (18″ or 24″) pots are ideal for these plantings. This will ensure that you can plant enough vegetables in each pot to make several spring salad bowls. As I said, I planted mine in Black Gold Natural & Organic Potting Mix, but this year I plan to try Black Gold Raised Bed & Planting Mix. Both mixes are OMRI Listed for organic gardening. My plant food of choice is a slow-release fertilizer for vegetable growing, though I often hit my plants with some water-soluble fertilizer a week after planting to help them take off.

Asian Salad Pot

There are many varieties of Chinese cabbage, mizuna, scallions, and romaine to try.

Asian Salad Pot: Spring Crisp Chinese Cabbage (63-65 days), Central Red Mizuna (40-55 days), Ishikura Improved Bunching Scallions (40-50 days), and Red Romaine Lettuce (56-60 days).

About the blend – This is a two-pot salad mix because Chinese cabbages are bulky. I am confident that the outcome will be worthy of a very tasty sesame salad dressing. The crisp, flavorful Chinese cabbage will combine nicely with the mustardy kick of the mizuna, the mild green-onion flavor of the bunching scallions along with the crunchy, sweet taste and bright color of the red romaine.

Planting tips – I recommend filling one pot with three Chinese cabbage heads with a sprinkling of mizuna around the exterior. Another pot can contain the romaine with scallions planted along the side. Be sure to space the scallions 2-3 inches apart. I always start cabbage, scallions, and lettuce plants indoors several weeks before planting outdoors. I start the seeds in 4-inch pots under grow lights. (Click here for growing tips.) Then I acclimate my seedlings to cool spring temperatures in my enclosed back porch. Scallions are often tender and slender at planting time, so be gentle with them and don’t plant their bulbs too deeply. One-half inch is perfect. The mizuna is a mustard green that can directly be sown in the pots at the time when you plant your seedlings–generally in late March or early April in my USDA Hardiness Zone 7 garden.

This spacing is approximate, depending on the varieties you choose. Just be certain to thin your scallions properly.

French Salad Pot

Chervil, butterhead lettuce, French radishes, and crunchy snap peas are a taste of France in a bowl.

French Salad Pot: Classic Garden Chervil (60 days), Divina Butterhead Lettuce (60 to 70 days), Flamboyant French Breakfast Radish (25-30 days), and Sugar Ann Snap Peas (52-62 days).

About the blend -The sweetness of the snap peas and butter lettuce blend well with the slight heat of the fresh French breakfast radishes. Chervil is added to provide a fresh, slightly anise flavor–much like the flavor of fennel. Together they taste very excellent with a classic French dijon vinegarette. If you are not partial to uncooked snap peas, try blanching them for a minute and then immersing them in an ice-water bath.

Planting tips – I recommend three large pots for this salad blend–one for the peas (a tomato cage makes an easy pea trellis), one for the radishes, and one for the butter lettuce with two chervil plants on the side. It is best to start the chervil and lettuce indoors under grow lights, as recommended for the greens above. The radishes and peas can be directly sown in the pots. Surface-sow the radish seeds and cover them with 1/8 inch of potting mix. Plant them in circular rows 6 inches apart and then thin them to 3 inches apart after they have sprouted. The peas should be planted in a circle at a distance of 3 inches apart and 1 inch below the soil surface. Time everything well, keeping in mind that the peas and greens need more time than the fast-growing radishes.

This spacing is approximate, depending on the varieties you choose. Just be certain to thin your radishes properly.

Italian Salad Pot

A salad of fresh chicory, romaine, and roasted Chioggia baby beets taste great with a fresh balsamic dressing and a touch of Parmesan cheese.

Italian Salad Pot: Chicory Bionda (35-45 days), Romaine Bionda Lettuce (55-60 days), Baby Chioggia Beets (40-55 days).

About the blend – The bitter bite of the chicory tastes nice with the sweet crunch of the romaine lettuce and sweetness of the baby beets. Chioggia beets are candy-striped with red and white bands inside, so they are as beautiful as they are delicious. The three taste very good with honey balsamic vinegarette and shaving of Parmesan cheese.

Planting tips – Two large pots are sufficient for this salad blend–one for the chicory and romaine lettuce, and one for the beets. The lettuce and chicory can be started as seedlings indoors, using the same recommendations for the two previous gardens. The beets should be directly sown in the pots. Keep in mind that the beets may germinate more slowly in cool weather, so you may want to plant them a week earlier than recommended on the packet.

This spacing is approximate, depending on the varieties you choose. Just be certain to thin your beets properly.

To learn more about great lettuce varieties, please watch this helpful video!

Why Won’t Tomatoes Grow Well in My Garden Box?

‘Sunrise’ sauce tomato shown. (Image thanks to Johnny’s Selected Seeds

“I have a deep garden box with soil and fertilizer. I plant tomatoes and they never do well. I am getting frustrated. This year will be my 3rd try!” Question from Janis of North Attleboro, Massachusetts

Answer: There are several reasons why your potted tomatoes may not be succeeding. I will list several potential reasons, and then provide some suggestions for this year’s container tomatoes.

Potential reasons for container tomato failure:

  1. The garden box is not draining well.
  2. The box is not big enough.
  3. You are watering too often or not often enough.
  4. You are growing indeterminate, or vining, tomatoes.
  5. Your tomatoes are diseased.

For your third try, follow these tips for success.

  1. Make sure your container is draining very well and its soil is fast-draining and porous. Also, consider planting your tomatoes in a larger pot. Watch the video below to see what size containers work for me.
  2. Add new potting soil. Tomatoes are susceptible to many soil-borne diseases (click here to learn more), so fresh soil is essential. Black Gold Natural & Organic Potting Mix is approved for organic gardening and my tomatoes like it.
  3. Feed with a fertilizer formulated for tomato growing.
  4. Choose a determinate, or bush, tomato that is certain to grow well in your Massachusetts climate. ‘Celebrity’ is an award-winning red slicer that always performs well in containers. ‘Glacier‘ is a flavorful cocktail tomato that grows well up North. ‘Sunrise’ sauce tomato is a super sweet, golden sauce tomato that is perfect for pots.
  5. Place pots in full sun and keep them evenly moist but not wet. Water most frequently in hot, summer weather.
  6. Cage your tomatoes.

I hope that these tips help!

Happy tomato growing,

Jessie Keith

Black Gold Horticulturist

Do Grubs Hurt Plant Roots?

Do Grubs Hurt Plant Roots?

“Do grub worms hurt roots? I have a lot in one of my containers.” Question from Jody of Live Oak, Florida

Answer: Yes they do. I’ll fully answer your question in two parts. First, I’ll address grub problems in the garden as a whole, and then I’ll address the grubs in your pots.

Grub Root Damage

Grubs are the larvae of many types of beetles. Most grubs feed on plant roots from fall to spring or summer, until they emerge from the soil as adult beetles. But, grubs aren’t always a problem. Under normal circumstances, you will not see the impact of a low to moderate grub population on large, healthy plants or lawns. They become a real threat when populations are high. This happens when fast-generating, destructive garden beetles, such as Japanese beetles, are not managed properly and populations soar. At this point management is essential. There are several steps you can take to manage destructive beetle grubs, and these are detailed in our Q&A blog titled, “How Do You Manage Japanese Beetles?” (click on the link to view).

Managing Grubs in Containers

Pots are small spaces, so a large number of beetle grubs will harm any plants within. Here are three easy ways to get rid of the grubs:

  1. “Grub” them out, and either smash them or place them in a pail of water until they drown. It is so fast and easy to do it this way if it doesn’t gross you out.
  2. Apply milky spore to your pots. This natural grub killer that just targets Japanese beetle grubs and is approved for organic gardening.
  3. Remove the potting soil from the pot, bag the soil in plastic, and wait several weeks before adding it to garden beds as an amendment. By this time the grubs should be dead. Add new mix to your pot for a grub-free start. (Click here to see our many potting soils.)

I hope that these tips help.

Happy container gardening!

Jessie Keith

Black Gold Horticulturist

Do You Think That Vegetables Produce As Well in Containers?

“Do you believe veggie plants grow and produce as well in large containers as planting straight in the ground?” Question from Donna of Newberry, South Carolina

Answer: It depends. It’s all a matter of plant size, rooting needs, container size, and overall care.

Container Size and Care

Large or standard-sized vegetables do not grow as well in containers because they need more space to reach full potential. Containers also require more upkeep in terms of water and fertilization, so gardeners often lose steam and quit giving them the right care, resulting in poor output.

Soil is another factor. Garden loams have more mineral content and water-holding ability, allowing for better, deeper root growth and development. For this reason, it’s nice to fill large pots with a mix of topsoil and an organic amendment (Example: 1 part topsoil to 3 parts Black Gold Garden Compost Blend). This will increase water-holding ability and add weight to top-heavy pots.

Compact Vegetables

For real growing success with container vegetables, choose the right vegetables. Compact or small plants yield better harvests. For an excellent list of compact vegetables, click here for a recent article on the subject.  It covers everything from tiny tomatoes to baby beets and mini melons.

More Related Articles

For more tips on successful veggie container growing, I encourage you to click here to read our full article about succeeding with container vegetable gardening. I also answered two similar Ask a Garden Expert questions: “What are the Best Root Vegetables for Containers?” and “What are the Best Edibles for Sunny Patio Containers?”

Let me know if you are having any specific troubles with your container vegetable growing.

Happy gardening,

Jessie Keith

Black Gold Horticulturist