Skip to content
Dahlia Society Of California
  • Home
  • Growing
    • Intro
    • Monthly Guide for Growing Dahlias in the Bay Area
    • 5 Simple Steps
  • Gardens & Hybridizers
    • Intro
    • Dahlia Dell at Golden Gate Park
    • Hybridizers Erik and Gerda Juul
    • Paradise on Earth
    • DJ’s Creation
    • South Coast Gardens
  • Web Resources
    • Intro
    • Online Informational Tools
    • Art and Photos
    • Books & Videos on Dahlias
    • Public Gardens
    • SF Dell on the Web
    • Dahlia Vendors
  • Newsletters
  • About DSC
    • About
    • Contact DSC
    • DSC Board
    • Meetings
    • Membership
    • Official Flower of San Francisco
  • Join DSC

Soil and Bed Preparation for Growing Dahlias (Page 6)

Dahlias prefer soil with a balanced supply of nutrients continued…

 

Determining Fertilizer Requirements When A Professional Soil Test Has Not Been Done

In the event that a professional soil test has not been done, there are other approaches to determining fertilizer needs.

 Soil Test Kit

  • Purchase a soil test kit from a garden catalog sales company or a local garden center and do a soil test and interpretation using the instructions enclosed. Such tests are rough estimates, but better than nothing. The tests are easy to do and do not take much time. They are usually limited to testing for pH, Nitrogen, Phosphate, and Potassium.
soil_test

Plant Nutrient Deficiency Symptoms

  • Based on observations of plants from the previous year, determine the nutrient deficiency from plant nutrient deficiency symptoms observed. See “Reading Plant Health, Improving Your Garden Soil”, Ortho Books 1992, for a comprehensive listing of nutrient deficiency symptoms. A major shortcoming of this approach is that the type of deficiency may be known, but how deficient it is will not be known. Plant nutrient deficiency symptoms for nitrogen, phosphate, and potassium are:

Nitrogen Deficiency Symptoms

  • Symptoms are mostly generalized over whole plant; plant light green; lower leaves are yellow; growth is thin and slender; symptoms appear first on lower leaves and work upward.
Deficiency
amonsulf1

Ammonium Nitrate – 34N

 

Phosphate Deficiency Symptoms

  • Plant is dull green, often developing red and purple colors; lower leaves sometimes yellow, drying to greenish brown or black colors; growth is stunted.
Deficiency
superphos25

Super Phosphate – 45P

 

Potassium Deficiency Symptoms

  • Symptoms are mostly localized; mottled or chlorotic leaves with small spots of dead tissue, usually at tips and between veins; leaf edges may roll up; squatty and stunted growth.
Deficiency
potash

Soluble Potash 60%

 

 Guess

  • Guessing typically gives unsatisfactory results. Plants may grow, but frequently are not vigorous and produce small blossoms.
sickplant

 

 

 

Previous Next

Share this:

  • Facebook
  • Twitter
  • Pinterest

Copyright 2017, The San Francisco Dahlia Society Web Hits
Theme by Colorlib Powered by WordPress