From the Digest

Seasonal Shift – Plan Before Moving Plants Outdoors

By David Wolfe (April 2008)

Photo“Plants are like people,” Mike Hellmann said in his March 2008 meeting handout. “They don’t always respond well to sudden changes and new situations.” But patience and planning can help limit problems as Midwestern cactus and succulent owners move their plants outside for spring.

In “Acclimating Your Plants to the Outdoor Growing Season,” HSCSS program coordinator Hellmann encouraged those in the full meeting room to move their plants outside in spring to give them more sunlight and fresh air for maximized plant growth, health and flowering. He and other speakers said that, based on conditions, most of their plants are out by late April with the remainder by mid-May.

Hellmann said basic planning is required for a successful moving process. Factors such as temperature, watering, light conditions and unexpected events should all be considered. “I hate to keep preaching this, but you really need to know your plants, too,” he said.


When it comes to transitioning plants to outdoor quarters, Hellmann advised, don’t go by the calendar only, as this can cause problems and create missed opportunities for more time outside. Watch the weather instead. Hellman said he regularly checks the 10-day weather forecast online.

When the timing looks good, he begins bringing plants out of his basement and greenhouse in order of cold tolerance. Those that tolerate cooler temperatures – usually cacti – come first, while his succulents from more tropical climates are moved later.

Reneé Jordan said she pulls her adeniums out of the greenhouse when overnight temperatures fall no lower than about 45 degrees. When the temperatures rise just a few degrees, her hoyas and other hanging plants soon follow.

Hellmann warned that since St. Louis weather can be unpredictable, growers should always be prepared to do “the dance,” quickly moving plants back indoors when unexpected cold snaps threaten.


Controlled watering prepares plants for the growing season by stimulating hair and feeder roots that were lost over the winter. These roots are necessary for plants to bring up water and resume growth, Hellmann said.

Begin to lightly water plants in February, March and April, depending on plants’ individual needs and situations. “The plants will tell you when to water more” with new growth and the onset of blooms, Joe Robertson said.

However, too much water all at once can cause problems in dormant plants. “Root rot can quickly take the fun out of a new growing season,” Hellmann said.

Outdoor Light

For the transition to spring, Hellmann directed hobbyists to initially move plants to outside locations with morning sun or filtered shade. Shade cloth, cheesecloth or even facial tissue can be carefully placed over plants to lessen the intensity of sunlight for individual specimens. Succulents “with lots of green” in their stems or leaves need particular protection, Hellmann said.

PhotoWayne and Michele Erickson, who overwinter about 80 percent of their plant collection under fluorescent lights in the basement, generally carry plants straight to large tables in the back yard. More delicate specimens, however, may at first be placed under the tables or nearby bushes to decrease their light exposure. Wayne Erickson said that packing the plants closely together on the tables not only provides a bit of shade for those at the rear, but keeps pesky squirrels away, too.

Hellmann said he acclimates plants for at least a week. For new plants or those with which he has less growing experience, he allows a longer adjustment period. On the other hand, Don Krechel, who is known for growing plants “hard,” was said to move his plants straight from under the bright lights of his basement into their summer positions with only a temporary cover of thin burlap to protect them from the sun. His striking specimens prove that approach can work, too.

Expect the Unexpected

To avoid unnecessary practice of “the dance,” Hellmann told his audience to expect the unexpected. Try to plan for the approach of cold fronts, high winds or extended periods of rain. In preparing for potential trouble, he recommended holding plants temporarily in flats or other containers to at least make dancing a faster and more convenient chore in emergency situations.

In closing his portion of the program, Hellmann recounted the tale of a spring hail storm that struck after his plants’ seasonal move outside.

He had strung a temporary cover over the plants, but not planned for it to bear a load. When the storm hit, he was not at home, so his wife did her best to handle both an umbrella and the shade cloth, which continued to sag as the hail rained down. When the shade cloth finally sank to the level of the thorny plants, some were literally plucked from their pots as the cloth whipped around in the wind.

Fortunately all the plants survived, although some had damage from the hail. Vickie Hellmann received a few welts, as well. Looking back, what may have appeared comical to neighbors could have been a very destructive situation.

“It’s funny now,” Mike Hellmann said. “But it sure wasn’t then.”