Guide to Starting Seed Indoors (2024)

FAQs

How to calculate when to start seeds indoors? ›

To determine the best time to start your seeds indoors, check the back of the seed packet to see how many weeks the seed needs to germinate and grow before it's transplanted. Using that number, count backward on the calendar from the average last frost date – that's May 15^th in our area.

Most seeds prefer a depth of about 2 times their length. The tiniest seeds can be sprinkled directly on the surface. Cover the seeds with a thin layer of soil. Plant about 3 seeds per hole (more if using older seeds) and once they germinate, thin down to leave only the strongest seedling.

Most seeds need a minimum of 14-16 hours of light per day to germinate and grow. Shop lights are a great option because they can be left on for long periods of time without generating too much heat but just enough for the plant needs.

If you start too early, you might end up with leggy, overgrown plants that need babying until the frost disappears and the soil warms. Start too late, and you'll be drooling over your neighbor's BLTs while forlornly waiting for your plants' blooms to turn into fruit.

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.

The radicle emerges first. The radical grows down into soil and forms root. The plumule grows up and continues to grow to penetrate out through the soil. It then forms shoot and leaves open out.

If only a few plants are needed, it is not necessary to plant all the seeds in a packet.

The rule of thumb is to plant seeds at a depth equal to two or three times their width. It is better to plant seeds too shallow than too deep. Some seeds, such as certain Lettuces or Snapdragon, need light to germinate and should not be covered at all.

Moisture Matters – After planting, water seeds with a gentle mist or shower. Avoid using a strong splash or spray, which can dislodge seeds. It is vital to keep soil consistently moist. In a sunny spot, this may mean watering twice a day.

What vegetables should not be started indoors? ›

Though some plants prefer to be direct sown (like squash and cucumbers), almost anything can be started indoors as transplants, if done right, including root crops like beets, radishes and turnips. The main exception are vegetables with long taproots like carrots and parsnips, which need to be direct sown.

For the healthiest seedlings, use a grow light to start your seeds. Healthy seedlings need a lot of light, and even a south-facing window may not provide consistent, even, bright light needed for plants to get a good start. Using natural window light risks producing long and leggy seedlings with skinny, weak stems.

Seed-starter mix.

It's usually peat moss, vermiculite, perlite, or coir depending on who makes it.

start indoors. General rule of thumb for most varieties is to start seeds six weeks before the last frost. Know your growing zone.

Even if the last thing you're thinking about in January or February is the garden, it's actually a great time to start seeds indoors for frost-hardy leafy greens and for slow-to-get-started herbs.

Seeds require a certain temperature to germinate. Each plant has a specific optimum and a range within which germination will occur. The closer the temperature is to the optimum, the quicker germination will occur. Most seeds germinate when the soil temperature is between 68° and 86°F.