Nitrate fertilization and root media effects on growth and shelf‐life of ‘honeycomb’ marigolds and ‘novette red’ impatiens¹

Received for publication: 9/22/91. Scientific Article No. A4930. Contribution No. 7973 of the Maryland Agricultural Experiment Station. As partial fulfillment of M.S. degree for senior author.

Abstract

Plants of Tagetes patula L. ‘Honeycomb’ and Impatiens wallerana ’Novette Red’ were grown in 4‐cell plastic containers (pack) using two different soilless media, Metro‐Mix 350 or peat:perlite (1:1 by volume), or a soil‐based medium, soil:peat:perlite (3:5:3 by volume). Both formulated media were amended with P and K and limed to desired pH. Although differences between media occurred, both species exhibited maximum growth and shelf‐life when fertilized with 100 mg N/L from NO₃ ^‐, as compared to those fertilized with 0, 200, or 300 mg N/L. Leaf tissue from the 100 mg N treatments contained lower N levels, but had comparable chlorophyll levels. As N concentrations increased beyond 200 mg N/L, shelf‐life was reduced. Plants receiving 0 mg N exhibited low visual quality and growth parameters; plants grown at 400 mg N/L had high mortality rates and were not marketable.

Notes

Received for publication: 9/22/91. Scientific Article No. A4930. Contribution No. 7973 of the Maryland Agricultural Experiment Station. As partial fulfillment of M.S. degree for senior author.

Research Assistant. Present address: Grace‐Soerra Horticultural Products 6656 Grant Way, Allentown, PA 18106–9316.

Professor of Horticulture.

Fromer Assistant Professor of Horticulture. Present address: 48 Brundrett Ave., Andover, MA 01810.