# Zinnias

Citizens Science Project: Biochar

An old garden favorite with may cultivars available, zinnias are bushy, leafy annuals that typically grow 1-3’ (less frequently to 4’) tall on upright, hairy, branching stems. Excellent fresh cut flower.

**Zinnias require** only about 44 pounds of nitrogen (N) per acre, or 2 pounds per 1,000 sq. ft, compared to pepper plants that need about 200 pounds of N per acre!

We are using the acre measurement because it is accessible online for commercial farmers. For home gardeners, we have made an easy-to-use conversion table that converts acres to the number of ounces your garden plot requires. If you want to find out how much N you need for your home or farm grown zinnias, use the calculator below. Before you add an amendment, though, have your soil analyzed for N content. Then make up the difference, if needed, by adding an amendment, whether that is a biochar/compost mix or commercial fertilizer.

Some tips when applying common fertilizers (from *A Homeowner’s Guide to Fertilizers*):

*A bag of 10-10-10 fertilizer contains 10 percent nitrogen, 10 percent phosphate and 10 percent potash.*

* **To calculate the pounds of nitrogen in a **50-lb bag of 10-10-10 fertilizer**, multiply 50 by 0.10. Do the same for calculating the amounts of phosphate and potash. A 50-lb bag of 10-10-10 contains a total of 15 lbs. of nutrients: 5 lbs. nitrogen, 5 lbs. phosphate and 5 lbs potash. The remaining weight is filler, usually sand or granular limestone. *

# Estimate Nitrogen Needs for Your Vegetable Garden

This website takes 3 types of data inputs and converts them into an estimate of how much nitrogen-based fertilizer is needed.## Input 1: Nitrogen (lb) per Acre

This calculator asks for the nitrogen needs for a crop planted in an acre because this value can often be found at the website of a county extension office or the land grant university in your state.## Input 2: Length and Width of Your Plot

## Input 3: Percentage of Nitrogen in your Fertilizer

Fertilizer purchased in a garden store will have a 3 number code on it. An example would be "12-3-7". This means the contents of the fertilizer package have 12 percent nitrogen, 3 percent phosphorus, and 7 percent potassium (potash). These are the three primary nutrients a plant will need. Enter the first of these numbers in the next field.