Question
QUESTION: I'm growing a number of annuals in a greenhouse and want to known what annuals need deadheading in order to increase blooming. I've already done my marigolds but I would like to get a listing so I know what others need this procedure.
Thanks

ANSWER: Deadhead EVERYTHING, Chuck.  Seed-making is exhausting for a plant.  It takes enormous amounts of energy and resources to bloom and go to seed.  The less energy they waste on any of that, the more is left for blooming and being beautiful.

This goes for perennials, tropical houseplants, herbs, bulbs, even trees and shrubs.

Remove spent flowers as soon as they begin their decline, and you'll get maximum pleasure out of the entire blooming season.

THE LONG ISLAND GARDENER

---------- FOLLOW-UP ----------

QUESTION: My situation is not in the garden but in a greenhouse growing environment. I want the seedlings to bush out without becoming tall and spindly. We have marigolds, geraniums, salvia, and other annuals. Thanks.

Answer
Ah ha!  You are not deadheading, my friend.  You are PINCHING.  That is a very good idea.

Note however you will delay flowering if you do this.  Professional growers not only pinch their seedlings and intermediate plants, they also treat them to a lot of growth regulators and plant hormones to obtain a stocky plant that will develop a lot more flower buds on lateral shoots than they would if left to Nature.  Pinching turns on the side-growth mechanisms and puts the flowering mechanisms on hold.  Nothing big -- just a small delay.  Possily significant for you, though.

A single pinching session ought to give you the best of both worlds.

The Long Island Gardener