Every guide on this site is grounded in real research — mostly from university extension offices, the same free, publicly-funded experts who’ve been answering gardening questions since 1914. This page collects the sources we cite most often, a glossary of terms you’ll see throughout our guides, and a good place to start if you’re new here.
Trusted Sources We Rely On
New Here?
Not sure where to begin? We’ve put together a full beginner’s walkthrough — the right order to tackle your first season, from picking your zone to your first harvest.
Find Your Local Extension Office
Nearly every U.S. county has a Cooperative Extension office — free, research-based advice from people who know your exact soil, climate, and growing conditions better than any website can. If you have a question specific to your yard, this is the best place to ask it.
National & Research Sources We Cite
These are the specific organizations behind the facts in our guides — not just general references, but the actual sources checked before anything gets published:
- USDA Plant Hardiness Zone Map — the official zone data behind our Zone Finder
- Cornell Composting — composting science and troubleshooting
- Cornell Cooperative Extension — vegetable growing guides
- University of Maryland Extension — seed starting and general vegetable care
- University of Illinois Extension — pest identification and harvest timing
- Iowa State University Extension — pruning and plant care
- University of New Hampshire Extension — tomato care
- Oregon State University Extension — composting and soil
- Ohio State University Extension — fruit disease and post-harvest handling
Glossary
Terms you’ll run into throughout our guides, explained simply:
Hardiness Zone — a USDA rating showing your area’s average coldest winter temperature, used to predict whether a plant can survive winter where you live. Read more →
Blossom End Rot — a dark, sunken spot on the bottom of tomatoes, peppers, and similar fruit, caused by inconsistent water delivery rather than a lack of calcium in the soil. Read more →
C:N Ratio (Carbon-to-Nitrogen Ratio) — the balance of “brown” and “green” material in a compost pile; getting it right is the biggest factor in how fast compost actually breaks down. Read more →
Hilling — mounding soil around a plant’s base as it grows, most commonly used with potatoes to prevent green, toxic tubers and boost yield. Read more →
Frost-Sweetening (Cold-Induced Sweetening) — the process by which certain vegetables convert starch to sugar after a hard frost, making them taste sweeter. Read more →
Leggy — describes a seedling that’s grown thin, pale, and stretched out from reaching for insufficient light. Read more →
Bacterial Wilt — a plant disease spread by pests like cucumber beetles that clogs a plant’s water-carrying tissue, causing sudden wilting even when soil is moist. Read more →
True Leaves — a seedling’s second set of leaves, which look like the actual plant rather than the generic first leaves; the signal that it’s ready for real potting soil and nutrition. Read more →
Seed Viability — whether a seed is still alive enough to germinate; declines with age at a pace that varies widely by seed type. Read more →
Determinate / Indeterminate — two tomato growth types that affect how much fruit a plant sets and whether pruning suckers actually helps or hurts your harvest. Read more →
Powdery Mildew — a fungal disease that coats leaves in a white or gray powdery film, thriving in humid conditions with poor airflow. Read more →
Nitrogen Deficiency (Chlorosis) — yellowing between a leaf’s veins while the veins themselves stay green, a common sign a plant isn’t getting enough nitrogen to produce chlorophyll. Read more →
Blossom Drop — when a plant’s flowers fall off before setting fruit, usually a stress response to heat rather than a sign of disease. Read more →
Botrytis (Gray Mold) — a fungal disease that causes soft, fuzzy gray rot, especially where fruit sits in prolonged contact with damp soil or dense foliage. Read more →
Transplant Shock — the temporary wilting and stalled growth a seedling shows after being moved to a new container or bed, usually caused by root disturbance. Read more →
Potato Scab — rough, corky patches on a potato’s skin caused by soil bacteria, generally cosmetic and safe to eat once peeled. Read more →
Soil pH — a measure of how acidic or alkaline your soil is, which directly affects how well plant roots can absorb available nutrients. Read more →
