Question
What kind of manure should I use for my flower garden and what kind for my vegetable. garden? Some people say cow and others say horse.

Answer
Both are excellent amendments.  All Manure carries valuable, slow-release levels of N-P-K PLUS micronutrients, Soil structure enhancements -- improved tilth, water holding capacity -- and other components of great Soil.

How much, exactly, varies.

And not just between species.

The same Horse will have varying values of minerals and other ingredients, depending on what that Horse ate for breakfast.

Highly soluble nutrients in raw Manure can evaporate or leach out -- especially Nitrogen, which turns into Ammonia in the absence of Oxygen.  The Salts in both Manures can do a number on plant roots and wipe out all microbes nearby, just like chemical fertilizer.

The solution:  Use ONLY COMPOSTED Manure.

Horse or Cow, it doesn't matter.  Any aged Manure SLOWLY sends nutrients into the Soil, enhancing the microbiological life.  Some approximate aged Manure stats:

Horse Manure: 7-3-6
Duck Manure: 6-14-5
Chicken Manure: 11-8-5
Rabbit Manure: 24-14-6
Cow Manure: 6-2-5

The book 'Teaming with Microbes' by garden writers Jeff Lowenfels and Wayne Lewis discuss composting and manures.  They maintain that the key to successful gardening is knowing the kind of Nitrogen you need for your vegetables.  What you need to ask is:  Will Manure give you that kind of Nitrogen?

There are two kinds of Nitrogen.  Most vegetables -- like most short-lived annual flowers and grasses -- perform best in Soil that provides Nitrogen in Nitrate form.  Your prettiest Annual flowers, your greenest Grass will grow best in Soil that makes Nitrogen that your plants like:  Nitrates.  NO3-.

Shrubs and Perennial flowers need different Nitrogen.  They need Ammonium.  NO2.  A Fungus-based Compost.  One WITHOUT Manure.

Bacteria that make NO3- (Nitrates -- VEGETABLE N) thrive in alkaline soil (pH above 7).  Just what your Vegetables need.  The tastiest, healthiest vegetables grow best in Nitrate based Compost.

otCautious authorities recommend against applying ANY Manure to a Vegetable Garden.  So you may want to avoid using Manure in Compost for soil where you will be growing edible crops. Even 'treated' Manure comes with no guarantees.

Both come with potential problems:

1.  Fertilizer Burn.  This is potent stuff.  You MUST age it before it's safe to use.  You'll find full instructions on 'How to Compost and Use Horse Manure' at the University of Illinois website:

www.age.uiuc.edu/clmt/manure_composting-farm-basics.pdf

2.  Weed Seeds.  Horse Manure can be filled with them.  Depends on who fed the Horse and what they used.  You will have to age it to use it without sowing a field of Weeds on your Garden plot.  The NRCS at the USDA posts a treatise on this subject, aimed mainly at farmers, but certainly of interest here:

www.nrcs.usda.gov/technical/ECS/nutrient/animalmanure.html

Don't rush it -- AGE as directed or you'll be sorry.

Otherwise, capital idea.  Thanks for writing.