Food-Gardening Lessons From A Wartime Victory Garden

What Are The Best Potting Soils for Dahlias, Lilies, and Begonias?

 

“What kind of potting soil should I use for Dahlias, Asiatic and oriental lilies, and begonias?” Question from Luciana of Portland, Oregon

Answer: Each flowering plant has some distinct needs when it comes to soil moisture, pH, and quality. The right kinds of fertilizers also help these flowers bloom at their best.

Soil and Fertilizer for Dahlias

Potted Dahlias need porous soil that drains well, holds moderate moisture and has a slightly acid to neutral pH (6.2 to 7). I recommend our Black Gold® All Purpose Potting Mix or OMRI Listed Black Gold® Natural & Organic Cocoblend Potting Mix, which is approved for organic gardening. Both potting soils have all the right characteristics. When picking a fitting fertilizer, choose one formulated for blooming plants. Proven Winners Premium Continuous Release Fertilizer is a good choice. Adding Proven Winners Premium Water Soluble Plant Food as directed will also help boost flowering through summer.

Soil and Fertilizer for Asiatic and Oriental Lilies

Lilies of all types grow best in soils that are well-drained and rich in organic matter. The ideal pH should be a little more acidic (5.5 to 6.5), but neutral soils are also tolerated. Once again, I recommend our Black Gold® All Purpose Potting Mix in addition to another of our OMRI Listed mixes, Black Gold Natural & Organic Ultra Coir, which is rich in organics but drains well. Here, it is best to choose a fertilizer specially formulated for summer bulbs. These tend to be balanced fertilizers with added bonemeal, and there are many fine choices on the market.

Soil and Fertilizer for Begonias

Fast-draining soils that are light and fertile are preferred by begonias. Their tubers or fibrous roots are prone to rot, so soils that hold onto water too well can be detrimental. Once again, a slightly acid pH (5.5 – 6.5) is needed. Black Gold® Natural & Organic Potting Mix is a good soil choice. Adding a little extra Black Gold Perlite for added drainage is also recommended. Proven Winners Premium Continuous Release Fertilizer helps boost flowering and performance in begonias. The occasional addition of Proven Winners Premium Water Soluble Plant Food will also help boost flowering.

Have a great gardening season!

Jessie Keith

Black Gold Horticulturist

About JESSIE KEITH

Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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