“When is the best time to fertilize Rhododendrons?” Question from Carin of Fall Creek, Wisconsin
Answer: When it comes to questions about Rhododendrons and Azaleas, even experts like me turn to the American Rhododendron Society. Their goal is to teach gardeners how to make the most of these beautiful flowering shrubs. Their advice follows that of professional growers: if the plants look happy, perform well, and have fertile, well-drained soil that is slightly acid, then there is no need to feed them. Excess fertilizer can actually damage their roots. But, if your soil is sandy and poor, then I recommend amending it with Black Gold Peat Moss and Garden Compost Blend to increase water- and nutrient-holding ability. From there fertilize in the early spring with a food formulated for acid-loving plants, like rhododendrons. (Click here to read more.)
“Do blueberries and strawberries need to be fertilized?” Question from Melanie of Holton, Michigan
Answer: Absolutely! Fertilization will encourage better growth, flowering, and fruit set. Each berry type has different needs when it comes to fertilizer.
Blueberries grow best in more acid soils (pH between 4.5 and 5.5) and require a specialty fertilizer formulated for acid-loving plants and/or berries. I generally fertilize in spring with a continuous-release fertilizer, but how you fertilize will depend on the product you choose. Follow the manufacturer’s application recommendations. There are many types of blueberry shrubs. To learn more, watch our video all about choosing and growing blueberries.
Strawberries like soils with a more neutral pH, and are less fussy. To encourage berry production, choose a specialty fertilizer formulated for strawberries or berries. There are many on the market. If your strawberries are June-bearing then I recommend fertilizing them in early spring and again later in the season, depending on what fertilizer you choose. If your strawberries are everbearing, then I would fertilize them with a continuous-release fertilizer in spring as well as a water-soluble fertilizer that will encourage them to produce berries through summer. For more information about growing strawberries watch this video.
“What kind of fertilizer should I use in my asparagus patch? What can I use to control the weeds in my patch?” Question from Linda of New Providence, Iowa
Answer: Asparagus is one of those spring vegetables that I think everyone should grow if they have the garden space. It’s so easy and so delicious. Here are some tips for easy weeding and care.
Asparagus Weed Control
When it comes to weed control, I always started by placing a wide cage around each asparagus clump to keep them upright through summer for easy weeding below. Staking and tying are two other options. Any caging or staking system will keep the rows looking good and make them more accessible for weeding. Then I add a layer of newspaper, wetted thin cardboard, or burlap mulch cloth along the sides of the asparagus rows and top it off with a thick layer of seed-free straw, leaf mulch, or grass clippings (sometimes all three). This step makes harvest less muddy, especially in moist springs, and keeps surrounding weeds down. Finally, I hand weed around my emerging spears. The use of a garden knife, or Hori Hori, will allow for effective precision weeding among clumps. If you don’t have a garden knife, it’s a good investment. Just be sure to keep Hori Horis out of reach from children because they are very sharp. I also recommend wearing strong gloves when working with one.
When it comes to fertilization, asparagus plants prefer balanced, low-nitrogen fertilizers (5-10-10), according to Stark Brothers, a good source for asparagus. I always used OMRI Listed fertilizer formulated for vegetables, which always worked well for me. I also like to occasionally add a layer of Black Gold Garden Compost Blend around the crown to act as a mulch and provide added organic matter.
“How often [do I] apply liquid plant food?” Question from Nancy
Answer: When it comes to water-soluble plant food, the application frequency and concentration depends entirely on the product, formula (10-10-10 versus a 20-20-20 NPK) and crop. Please let us know what you are growing and product details! Also, when it comes to application guidelines, always refer to the instructions on the product label. Happy Gardening!
“My blueberry plants have yellow leaves. Why is this happening and what can I do?” -Question from Emily of Columbus, Ohio
ANSWER: Your blueberries have chlorosis. This is caused by a soil pH problem. Blueberries like acid soils between 4.5 and 5.5. When soils are too alkaline (have a higher pH) blueberry plants cannot access necessary nutrients, and their leaves start to turn yellow. Thankfully, this problem is easy to fix.
First, it helps to determine the pH of your soil. Take a soil sample to your local Ohio State University Extension Service (click here for instructions). Once you get the results, you will know how much you need to lower your soil’s pH for your berries.
You can lower soil pH by amending with Canadian Sphagnum Peat Moss and adding a soil acidifying fertilizer around the base of the plants. Aluminum sulfate will quickly lower soil pH; there are also other brands of soil acidifiers and acid fertilizers specialized for crops like blueberries. Follow the instructions on the packaging to adjust the pH around your blueberries, and they should bounce back in no time!