“What is the best soil mixture for potted rosemary and lavender?” Wakenda of Portland, Oregon.
“Can watermelon vines be grown in containers?” Question from George of Hagerstown, MD
Answer: Watermelons can be grown in large containers if you choose a compact variety. Here are my recommendations regarding potted watermelon culture.
First, choose a more compact, short-vine watermelon variety suited for container growing. ‘Cal Sweet Bush‘, a 2019 AAS award winner, has excellent melons and vines that do not take over, and ‘Bush Sugar Baby‘ is another small-vined type with tasty melons. Next, choose a large container that’s between 18 to 24 inches. There must be holes at the bottom for drainage. Plastic or glazed containers hold water better in the heat of summer. Fill the pot with quality, porous potting soil that holds water well. I would choose Black Gold Natural & Organic Raised Bed & Potting Mix. Place the pot in a spot where it gets full sun, and the vining stems can hang down and spread a little. Patios or open garden areas work well for large potted vegetables like this.
Plant one or two watermelons in the pot in spring after the threat of frost has passed. Keep the soil moist. When the vines have reached a good size in summer, water daily in the absence of rain. Fertilizer well from the beginning. A good slow-release fertilizer formulated for vegetables is ideal. Be sure to follow the manufacturer’s application instructions.
Melons should start to appear by late July or August.
Happy melon growing!
Jessie Keith
Black Gold Horticulturist
“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
“What is the best potting mix for Meyer lemon tree in a plastic pot? Needs to drain well.” Question from Polly of New Mexico
Answer: We offer several good-fit mixes. Before potting your tree, make sure that the new pot is several inches larger than the old and that it offers excellent bottom drainage. The ideal potting soil should have a balance of good porosity, drainage, and water-holding ability. Ideally, it should be slightly acid, because Meyer lemons grow best in soils with a pH of 6-7. Here are our best OMRI Listed soils for your tree.
Potted citrus trees require a minimum of 8 hours of sunlight a day to perform well. Warm growing conditions (60 – 75 degrees F) and moderate humidity (45 – 50%) will encourage flowering and fruiting. Bringing plants outdoors in summer, on a sunny porch or patio, helps them grow better year-round.
Good watering, feeding, and care practices will keep your plant happy. Water plants deeply until the water drains from the bottom of the pot. Allow pots to become moderately dry between watering–the tops should be dry down to a minimum of 3 inches. (Outdoor plants may need to be watered almost daily, while indoor plants require less frequent water.) During the winter months, when growth naturally slows, the watering regime should be reduced. Signs of overwatering include leaf yellowing and drop and eventually stem death. Trees allowed to become too dry may also unexpectedly drop some leaves.
Fertilization is essential, any slow-release fertilizer formulated for citrus would be ideal.
I hope that these tips help!
Jessie Keith
Black Gold Horticulturist
“I live in Southwest Florida (Englewood, FL) to be exact. I bought 3 Pomegranate Wonderful trees and planted them about 3 years ago. They’re really not doing much of anything. They just exist. They refuse to flower, they barely have grown at all, and one just clings to life and is constantly yellow. I planted them with storebought soil at the base, and fertilize with 6-8-6. They are in almost full sun, get plenty of rain this time of year…but they just don’t do anything.” Question from Nikki of Port Charlotte, Florida
Answer: Pomegranates are Mediterranean and Middle Eastern fruits adapted to cooler winters and hot, dry summers. Florida is not their ideal climate. They need heat, dry weather, and rocky, well-drained soils. As horticulturist Maureen Gilmer wrote: “So long as the local climate is within the cold tolerance range (USDA Hardiness Zones 8-11) and summers are not humid and rainy, pomegranates should thrive. Untimely rains in the fruit’s late-summer and fall ripening season can also cause rinds to crack open prematurely, spoiling the contents.” (Click here to read the full article.) They also like a soil pH range of 5.5 to 7.2. If your soil is more acid or more alkaline, then they will struggle to get the nutrients they need, which may explain the leaf yellowing. Excess water can also cause leaf yellowing and encourage fungal disease.
You can create sandy, rocky mounds for your trees, but your better bet is to grow them in large pots in a sunny spot under cover from the rain. Once you can control how much water they get, water them weekly after they become established. More water is needed as trees as setting roots and during very hot times.
Choose a large pot that’s several inches larger than the tree’s root balls. We recommend planting in a well-drained potting mix. Black Gold® Natural & Organic Flower and Vegetable Soil with 1:5 ratio of soil to Black Gold Perlite for increased drainage would work well. Feed with a fertilizer formulated for citrus trees. Follow the manufacturer’s directions. (Click here to read our full article with basic potting instructions.)
As your trees grow, prune them as needed in late winter. Any long suckers or crossing branches should be removed.
We hope that these steps lead to many flowers and pomegranates!
Happy gardening,
Jessie Keith
Black Gold Horticulturist
My Plumeria needs repotting. What is the best soil and pot type? What amount of sunlight is best – morning, noon? Watering schedule? Question from Jean of Diamond Bar, California
Answer: Frangipani or Plumeria (Plumeria species) shrubs are tropicals that are native to Mexico, Central America, and South America. There are many species that have been bred to create a fine array of colorful varieties–nearly 400 garden varieties are registered.
There are several things that plumerias need to grow well. They grow and flower best with full sun (6 hours or more per day) and warm temperatures (60 to 90 degrees F). Because they are susceptible to root rot, they require contains and potting soil that is slightly acid (6.4 to 6.8 pH) and drains well. Black Gold All Purpose Potting Mix with a little added Black Gold Perlite would be ideal. There are specialty plumeria flower fertilizers on the market or you can choose, or you can simply use a fertilizer formulated for flowering shrubs.
Repot your plumeria every two to three years. A new pot should be at least three inches larger than the last. Plumerias emit a milky latex when damaged, which can be irritating to the skin and eyes, so wear garden gloves and long sleeves when repotting them.
Cover the bottom of the pot with a shallow layer of mix. Then gently lift your plumeria out of its old pot. Adjust and center the root ball in the new pot. Add new soil to the base as needed. Once planted, there should be 2 inches of headspace at the top for watering. If the roots are intertwined, or pot-bound, then gently tease them apart along the bottom and sides to increase establishment and water and nutrient uptake.
Add fresh mix along the sides and work it down firmly to increase soil-to-root contact and remove air pockets. Water in your new plant until water runs from the bottom of the pot. Fill in any receded spots along the sides and water in again. Begin to fertilize a week or two after planting. Follow the manufacturer’s recommendations.
Happy plumeria planting!
Jessie Keith
Black Gold Horticulturist