Question 1

How long do seeds stay viable?

Accepted Answer

From one year to several decades, depending overwhelmingly on the **species** and then on **storage conditions** — and the difference between species is far larger than most seed packets suggest.

**The short-lived, which should be bought fresh annually:** parsnip, which is notoriously poor after one year; onion and leek; and many alliums generally.

**Moderate, around two to three years:** carrot, parsley, sweetcorn, peppers, and many flowers.

**Long, four to six years or more:** tomato, cucumber, courgette, squash, melon, brassicas, beans and peas, lettuce, radish and beetroot. Squash family seeds are particularly durable.

**Why they differ.** Seeds are alive but nearly inert, respiring extremely slowly. Deterioration comes from accumulated damage to membranes and DNA and from depletion of reserves. Seeds with oily reserves generally deteriorate faster than starchy ones.

**The storage rule that governs everything.** A widely used guideline is that the **sum of temperature in degrees Fahrenheit and relative humidity as a percentage should be below 100** — so cool and dry, with dryness mattering more. Each roughly 1% reduction in seed moisture, or 5°C drop in temperature, approximately doubles lifespan within working ranges.

**In practice:** an airtight container, in a cool dark place, with a desiccant sachet; a fridge is excellent provided moisture cannot enter; and **a shed or greenhouse is the worst place**, because both temperature and humidity swing.

**Why seed banks freeze.** Long-term conservation dries seeds to low moisture and stores them at around −18°C, giving lifespans measured in decades or centuries for many species. Some seeds — **recalcitrant** species including many tropical trees and acorns — cannot be dried and frozen at all, which is a real conservation problem.

**How to test before sowing.** Place ten seeds on damp kitchen paper in a sealed bag somewhere warm, and count how many germinate after the expected period. Seventy per cent means sow normally; thirty per cent means sow three times as thickly or replace.

**Germination rate falls before viability ends**, so old seed germinates slowly and unevenly rather than not at all.

Question 2

Why did my seeds fail to germinate?

Accepted Answer

Almost always one of five things, and the order below is roughly how often each is the culprit. Temperature. This is the most common cause and the least visible. Every species has a soil temperature

Question 3

Why do some seeds need a cold period before they germinate?

Accepted Answer

Because they have a built-in dormancy mechanism that prevents germination until the seed has experienced winter — an adaptation that stops seedlings emerging at the wrong time of year and being

Question 4

What are the most common vegetable gardening mistakes?

Accepted Answer

Avoiding common vegetable gardening mistakes is essential for successful gardening. Key errors include poor soil prep, improper watering, and neglecting pest control.

Question 5

How to grow vegetables in containers?

Accepted Answer

Growing vegetables in containers allows for gardening in limited spaces. Choose the right containers, select suitable vegetables, and ensure proper care for successful growth.

Question 6

What is crop rotation and does it matter in a small garden?

Accepted Answer

Crop rotation means not growing the same family of vegetables in the same ground year after year, moving them around a sequence of beds instead. What it is actually for. Two distinct problems, and

Question 7

What is a cold frame and do I need one?

Accepted Answer

A cold frame is a low, unheated box with a transparent lid — traditionally a wooden or brick frame with a glass "light" — that traps solar heat and shelters plants. It is the cheapest and most useful

Related Questions