Step by Step: How to Grow from Seed

10 Steps

Spring is here, so you might need a step-by-step program for growing seeds. Whether you’re a gardening newbie or a veteran farmer looking for extra tips, below you’ll find “seed growing best practices.”

1: Start your seeds on wet paper napkins

Simple wet a paper towel thoroughly, lay half of it on a plate, spread out your seeds on the wet towel, and then fold the other half loosely over the seeds. Ideally, you want some airflow between the two layers. Just be sure not to submerge them in water. You’ll soon seed little roots breaking through the outer shell.

We usually use lukewarm water, spritzed a few times a day. The key is to keep the seeds wet to allow root growth. The seeds don’t need much light at this stage, but they will later.

2: Place your seeds in your germination tray

As soon as the seeds begin to germinate, gently remove them from the paper, and place them in your seed starter tray soil. We use rubber-tipped tweezers to avoid pinching the seeds too much. Pinching with fingers can be destructive. Remember, they’re soft at this stage, so delicacy is a must!

We usually plant 3 seeds per cell, then cull the two smallest ones as they grow. Although it hurts to cull young, healthy seedlings, if you plant only one seed per cell, you run many risks — e.g., they don’t fully germinate; they aren’t strong; they’re small, etc. Since growing seeds is a long-term investment, take out the extra insurance and plant more seeds than you need per cell. Trust us; it’s a must!

But what kind of soil? You can find special “germination soil” online or at the local store, but it isn’t necessary. Regular potting soil works fine. Just make sure it drains well. If your soil is too fine (e.g., clay-like), it can become compacted, and the roots will not have freedom to grow. Ultimately, your plant growth will be stunted. On the other hand, if your soil is too loose, it won’t retain saturation. Fluffy soil that retains moisture is best.

3: To cover, or not to cover?

Covering your germination trays can help protect your delicate seedlings from abrupt temperature changes and retain moisture, but such trays also run the high risk of fungus growth. Anytime you have moisture + warmth, it creates an environment for bacterial growth and pathogens. Be sure to monitor your trays if you use a humidity dome, and always ventilate to avoid stagnant, non-airflow.

4: Water

Once you’ve covered your seeds with soil — be sure read your seed packet instructions on how to do this — it’s time to gently water. The key here is to gently water; don’t flood your cells. Spritzing them works best.

As a DIY at home, I’ve reused plastic water bottles to water the seeds. Pierce the cap with a thumbtack, making a circle of holes in the cap. Fill it up with water and squeeze. It comes out gently, and it is much faster than spritzing with a water bottle.

Photo: Markus Spiske — Photo: **Markus Spiske**

5.) Light (and lots of patience)

Once your seeds have been watered, they need two things: 1.) light and 2.) time to grow. You’ll eventually begin to see tiny seedlings rise from the soil. Some seeds sprout within a couple days, others take up to two weeks. Like people, some seeds grow much faster than others, even when they have the same family genes.

If you propagate indoors, keep them near a window with sunlight, rotating the tray every day to balance sunlight. If you propagate your seeds in a backyard, be sure the temperature conditions are mild and stable. In terms of how much sunlight, I use the graduated method. Start off with a few hours of sunlight each day, then increase. Yes, seedling leaves can sunburn, usually indicated by yellowed or burned-looking leaves.

Though seedlings need lots and lots of sunlight to photosynthesize and grow, too much sun creates what are called free radicals. Basically, this means that the plant is absorbing more energy than it can use, thus creating a reactive species of oxygen that can destroy the plant.

Best practice: monitor your seedlings everyday. If they look sunburned, put them in the shade.

6: Moisture, ventilation, warmth, and good draining = success

Moisture: Saturate the soil, keeping sure that the bottom of the soil is just as wet as the top. You want those roots to dig deep!

Ventilation: Keep a fan or some sort of airflow near your tray. Don’t keep them in a dark, dank basement with no air circulation. Humidity domes are especially prone to non-ventilation and fungus growth, so if you use them, keep the air flowing.

Warmth: Keep near a sunny window or on a warm counter top at night. It’s okay if it’s cold at night, just keep them indoors. If outdoors, put them under a cloche or humidity dome to protect from the elements.

Drainage: Like any living organism, all plants emit waste. Without drainage, plants will decay in their own excretion, causing the roots to rot.

Sili-Seedlings seed starting trays are made from 100% Silicone

7: Culling

This isn’t for the faint of heart.

If you dropped three seeds in a single cell, you should logically expect three plants beginning to grow. But you want one plant per cell, not three. So, as the seedlings grow, you’ll see some grow stronger, more robust, and larger than others. Those are the ones with the best genetics — keep those! The others, unfortunately, didn’t make the “cut.” So, you need to cull (kill) those. Sorry little dudes, no hard feelings.

NOTE: Be sure NOT to pull out the culled seedlings; instead, snip them with a knife or shears until only one remains.

8: Transplanting Seedlings

When seedlings grow their second set of leaves, getting about 3-5 inches in height, it’s time to transplant the seeds. Here are some tips on doing so:

a.) Acclimate the seedlings to the outside 3-5 days before transplanting to avoid environmental shock. Put the tray near where you will plant them for a couple days before transplanting them.

b.) Don’t water your seedlings the day of transplanting. Wet soil can make the plant very difficult to extract from the cell — they tend to fall apart. Moderately dry soil keeps the integrity of the plant’s roots intact, and makes the transplanting much cleaner.

c.) Plan where you will transplant your seedlings and dig holes BEFORE extracting them. Try to minimize the time the seedling is extracted from the cell. Ideally, it should go directly from the cell to the ground or garden bed.

9: Sterilizing your Seedling Trays

This should not be overlooked. No matter how sterile your soil is, you’ve created a warm and moist environment for your seedlings to grow over the past 3-6 weeks. Unfortunately, this fertile ground is loved by your plant’s biological cousin: pathogens!

I suggest washing (sterilize is best) your seedling trays after every use. Sili-Seedlings are silicone and dishwasher safe, so you can sanitize them there. We recommend blasting them with a hose to remove excess dirt, then boiling them in a pot for 5 minutes to kill off any pathogens. Simply scrub off any remaining residue with soap and water.

I don’t recommend using plastic cells for a variety of health, biological, and environmental reasons.

10: Manipulate your plants to grow the way you want

This depends on the kind of plant you’re growing, but there is a general concept worth mentioning.

Plants produce their own glucose — the stuff that makes cells — from photosynthesis. We humans get glucose from food, not from the sun, unfortunately. So, plants have a finite amount of glucose gained from sunlight.

Vegetable and fruit plants can use their energy in one of two ways: 1.) grow fruit or 2.) grow leaves. You, as the grower, need to decide where you want that energy going.

Tomatoes are a great example.

Suppose a very young tomato plant begins to produce a string of tomatoes. Since it is using its glucose towards fruit production, the plant will not grow very big. Why? Because you’ve allocated its glucose to fruit production, not to stem/leaf production. Have you ever seen a tiny plant spent all of its energy on making one really big tomato? It’s sad..

I personally don’t let my tomato plants grow fruit until the size of the plant is as big as I want it. Until the plant reaches the size I want (for indeterminate varieties, usually 5-6 feet high), I immediately pinch off its flowers to ensure it uses its energy to grow leaves, not fruit. As a result, my tomato plants grow very quickly, and when the plants are fully mature, I devote all their glucose towards making delicious, juicy tomatoes. To stop growth, simply pinch off the tops of the plant.

If you have any questions or suggestions, please contact our team of gardeners, and we’ll be happy to get back to you within 24 hours! Happy Gardening!

Ryan SauchelliApril 22, 2019Comment