Temperature influences the moisture content, hormone function, and enzyme activity that occurs during seed germination. Warm temperatures accelerate the chemical reactions in seeds and accelerate cell formation for development.
All seeds will germinate within a range of temperatures, some wider than others. Peas, for example, will germinate in soils as low as 40 F, though they germinate best between 50 and 75 F. Their optimal temperature to germinate fastest is 75 F. In 40 F soils, your peas may take 2 to 3 weeks to germinate.
Each plant has a specific optimum and a range within which germination will occur. The closer the temperature is to optimum, the quicker germination will occur. Most seeds germinate when the soil temperature is between 68° and 86°F.
Temperature affects germination in three primary ways: moisture, hormone production, and enzyme activity. For seeds to germinate, they need to imbibe water. For this to occur, sufficient moisture must be present. A warmer climate may increase evaporation and decrease moisture, which would negatively affect germination.
*Hot Soak - you can break seed dormancy much quicker with some species if the seeds are exposed to hot water. We usually place these seeds in about a cup of 180o F water (80 o C) and let them soak (and cool) overnight before planting.
Pre-Soaking.
This method could be the fastest way to germinate seeds. Place seeds in a shallow container in warm water and leave them for 16 to 24 hours (smaller for 16, bigger for 24). Remember not to expose seeds to temperatures higher than 80°F (26.6°C) and not to pre-soak seeds for more than 24 hours.
Key Factors in Germination
The three primary factors that regulate seed germination are moisture, temperature, and oxygen. Light is also an important influence on germination in some species. Moisture in adequate amounts, as stated above, is critical during germination and seedling growth.
All seeds need warmth and moisture to germinate and grow on well. How much warmth varies by type of vegetable – for example broad beans will grow fine in soil temperatures over 8 degrees C, whereas aubergines need much more heat; ideally over 24C.
For many garden plants in fact, a soil temperature below 50°F can be a problem. With temperatures in the 40s, seeds will readily absorb water, but not start to grow. This creates an opportunity for disease and rot, which can result in damping-off or poor growth.
All seeds need water, oxygen, and proper temperature in order to germinate. Some seeds require proper light also. Some germinate better in full light while others require darkness to germinate.
Light is not necessary for a seed to germinate, no. The majority of seeds grow most effectively in the dark. Light, which is essential for seedling growth, may actually hinder the germination process. The three primary and necessary conditions for a seed to germinate are water, oxygen, and temperature.
The best temperature to germinate most seeds is about 80°F (27°C). Many commonly-planted garden seeds will germinate in a week or two when the temperature is in an optimal range between approximately 65-85°F (18-29°C). Germination time and temperature varies between seed species and even cultivars.
Some seeds take a long time to germinate, and seed soaking can help to speed up the process. By soaking seeds in lukewarm water for 8-12 hours (some can go up to 24 hours, but never more than that), you help the seed to break dormancy and germinate faster.
Within a week, temperatures in a properly constructed compost pile will reach 130 degrees Fahrenheit. That quickly kills many seeds and stabilizes the composted material. But it takes 30 days of exposure to temperatures of 145 degrees or more to kill seeds from tougher weed species.
Move the container to a warm, draft-free spot where you can check it daily. Most seeds germinate best when the temperature is between 65 and 70 degrees Fahrenheit, but check the information on the seed packet for specifics.
There are four environmental factors that affect seed germination: Water, Light, Oxygen, and Heat. Check out these four tips to learn how much of each and when.
As it turns out, you can! Hydrogen Peroxide 3% - Oxygen PlusTM, a food-grade solution made in pure distilled water, can effectively increase germination speed and support the growth of strong, healthy plants.
Seeds need to be moderately moist to sprout. Seed germination is highly dependent on watering. Too dry and they won't get the message to sprout, too wet and they will rot in the dirt.
Once dormancy is broken, seeds may germinate within 3-12 weeks. Seeds with delayed breaking of dormancy generally take 3-8 months to germinate. Seeds usually germinate within 2-6 weeks at 75-85F. Variable, some seeds sprout within 1-3 weeks, others take much longer.
One of the most popular ways to germinate seeds is the paper towel method.
Many seeds germinate much quicker in paper towels (versus seeds that are started in soil). The heat, moisture, and controlled conditions inside a plastic baggie help them germinate in only a few days (or less, depending on the seed).
If the seeds are really fresh, some will germinate in as little as 1 day! The fastest germinating seeds include everything in the cabbage family – bok choi, broccoli, kale, cauliflower etc, and lettuce. The slowest seeds to germinate are pepper, eggplant, fennel, celery, which may take 5+ days.
The warmer the environment, the faster the germination. The best average temperature to grow your plants is 18 to 24 °C (64 to 75 °F). Usually, it takes around 1 to 2 weeks to germinate.