Back to Teaching Suggestions

Factors to Investigate
How are these factors related to plant growth?
Use this reference page to help you complete the Gardens Comparison Chart.

Sample Sources of Information


Find the latitude and longitude of a garden site on Journey North's map or list of test gardens:


Shaded relief maps show elevation. Find the elevation of a garden site here:

Proximity of Oceans

Explore world maps to measure distance from a garden site to the nearest oceans.

Day Length

Find the sunrise and sunset times at a garden site and calculate day length:

  • Sunrise and Sunset Look-up Tables: USA/World


Explore today's temperatures. Use your own thermometer to find your current temperature. Look up temperatures at other garden sites here:

Climate Data

Explore the average, high, and low temperatures for a garden site at these links:

Historical Data
from Tulip Test Gardens

Look at test garden data from past years. Find the dates tulips typically emerge and bloom at different test garden sites. Can you find patterns of plant growth?

Plant Hardiness Zones

This map of North America is based on climate data. It shows zones with similar average minimum winter temperatures. Plants must be hardy enough to survive the coldest temperatures that are typical for these zones. Gardeners use this map as a guide for safe planting.