Cultural Information

Pre-Plant Conditions

Starting Material

Seeds are received at the MSU Greenhouses during the winter and early spring months.  Each seed variety is sown at the appropriate date so that the finished plants are ready for transplant during late May and early June. Seeds are sown in flats or plug trays and germinated under regular mist treatments at 75 °F.   After germination, seedlings are transplanted into 4” containers or 1204 flats. 

Cloned plants are propagated by cuttings or tissue culture at offsite commercial greenhouses.  Rooted cuttings are shipped as plugs to the MSU Greenhouses.  Upon receipt, the rooted cuttings are transplanted immediately into 1801 flats.  Most plugs are received and transplanted during March and April. 

Greenhouse Conditions

After transplanting, all seed and vegetative material is grown in glass greenhouses set at ~75 °F daytime and ~68 °F nighttime temperature until they are transplanted outside.

Plants are grown in a peat-lite soil mix (2-B Mix), generously donated by Sun Gro Horticulture and fertigated at every watering with 19-4-23 (125 ppm N) water soluble fertilizer.

Container Plants

Companies are given the choice of trialing in containers or ground beds.  When requested, plants are planted into 22” containers and held in greenhouse for about 2 weeks before placing them outdoors during late May and early June.  Some plants are tested in ground beds and containers.

Outdoor Ground Bed Management

Bed lines were marked and sprayed with Round-Up.  Some beds lines were hand cut, while others were cut with a mechanical edger.  Round-Up was applied where necessary to control weeds before planting. 

Plants are typically planted at 8” -12” on center depending on the species.  We typically plant at least 24 plants per trial entry in landscaped beds. Due to space restraints, fewer plants are planted for each native plant and vegetable entry.


Summer Maintenance of Trials


All beds and containers are hand watered as needed. 


As needed, beds are fertigated with a 19-4-23 (250 ppm N) water soluble fertilizer every two or three weeks.  We do not give more than this since it is of interest to learn which plants do better with less fertilizer.  Petunias and calibrachoas are fertilized with Jack’s Petunia FEed Plus Magnesium (20-3-19) to maintain a low media pH and prevent iron and magnesium deficiency.


All beds are hand weeded and cultivated as needed until plants filled in.  Long hours of hand weeding are required to keep the beds looking good.  Volunteers help a great deal on this tedious task!

Disease control

No treatments are given this year for insect or disease control in the annual gardens.  Other than typical damage from Japanese Beetles, relatively few troublesome insects or disease pests are noted each year.


Geraniums, dahlias, cannas, salvias, snapdragons, marigolds, verbena, and zinnias are deadheaded throughout the season as needed.  Some cultivars required far less dead-heading than others – certainly a desirable trait!

Hanging Baskets

Almost all the hanging baskets seen in the MSU Horticulture Demonstration Gardens are generously donated by Four Star Greenhouses (Carleton, Michigan).  They are received in June as finished baskets.  They are watered and fertilized daily with a 19-4-23 water soluble fertilizer at 250 ppm N.