Guide to Starting Seeds Indoors-An Introduction

I’ve started seeds indoors many times. I’ve read countless articles and books, watched videos, etc. and all I’ve really learned are the steps required to plant seeds. I have acquired knowledge with experience, as far as what works and what doesn’t but I didn’t really have an understanding of why the steps were necessary or what was happening throughout the process. I also think most of us scramble during gardening season to answer questions as problems arise looking for the fastest and best solutions. The problem with this approach, for me, and I suspect many others, is that we are trying to learn all of the rules in a system where there are a gazillion rules with an equal amount of exceptions.

This year, I’ve changed my approach. I’ve been researching botany, especially as it relates to gardening. Having a deeper understanding of the whole process has really increased my success ensuring that my plants are healthy and happy and my harvest is bountiful. So, let’s dig deep into the process so that your harvest will be bountiful too.

The Seed

Let’s start our look at the growth cycle of a plant with the seed. Seeds appear to be as active as a stone and while we do refer to them as being dormant, they are anything but. Inside that tiny seed, metabolic processes are occurring in order to create all of the things the seedling will need to grow the moment conditions are right for germination.

The outside covering of the seed is called the seed coat. The color, texture, and thickness of the seed coat vary from species. These variations are what dictates the length of time and requirements needed for germination. For example, a seed with a thicker seed coat may require scarification, a process that occurs in nature via bird beaks, stomach acids and the like but can be replicated by gardeners by making slices in the seed coat with a sharp knife or scuffing it with sandpaper or file, or you can use acid but…it’s acid…so…maybe not that one.

Inside the tiny seed is a seed embryo. This embryo is a super tiny miniature plant. It has a root, a short stem, seed leaves called cotyledons and these even have veins. This embryo is what will grow once the seed germinates.

Germination

There are three requirements for germination. The seeds require water, temperatures between 70 and 80 degrees Fahrenheit (21-27 C), and a well aerated soil. Once the seed has had contact with that warm moist soil, it begins to take on water. The inside of the seed swells causing the seed coat to split. This creates easy access to water and oxygen in the soil for the embryo and cotyledons. The root is the first thing to emerge and it begins to branch in several different directions. The hooked stem pulls the cotyledons and then together they pull the stem tip out of the soil. Once the cotyledons are above the soil, the stem straightens and the embryo leaves expand and turn green and a seedling is born. 🙂

The Primary Growth Phase

The seedling now begins its Primary Growth Phase. During this initial phase, the seedling is completely dependent on the seed’s own food store (the cotyledons). The focus, at this stage, is on root growth and the growth of the shoot system, which is the stem, leaves, and branches. Taking a moment to better understand these parts and how they grow will prove beneficial, not just when planting seeds but also later when you’re making decisions about watering, fertilizing, and pruning in the garden.

The Roots

There are two main types of roots. Tap roots, which have one or two sparsely branched roots that grow rapidly down and deep into the soil. Carrots, Beets, Sweet Potatoes, Radishes, Oaks, and Pines are all examples of plants with Tap Root systems. There are also fibrous roots, which grow close to the surface and have many different branches. Corn, Wheat, Grasses, Rice, and Onions all have fibrous roots. Some plants also have a combination of the two, like tomatoes and some trees. It’s a good practice to research every plant that you would like to add to your garden so you can make the best decisions about its placement and care. There are so many exceptions to the rules of the plant kingdom and thus to the rules of gardening. Learning about every plant you grow will ensure you know the exact needs for that species. If you plant a seed with a fibrous root system and then water and fertilize it too deeply, it won’t prove beneficial to the plant. If you know it has a fibrous root system then you know that you will need to water lightly and more often and that fertilizer will be more beneficial if provided at the surface. But, I digress. Back to root growth. Roots grow from the tip of the root, called the growth tip, oddly enough. Their primary objective is to increase in length. They absorb water a short way behind the growth tip via root hairs which significantly increase the surface area allowing for more water and mineral uptake. The older sections of the root are where branching occurs.

The Stem and Shoot System

Stems are primarily responsible for support and the transport of water and nutrients. Stems also grow from a growth tip, not called a growth tip…again, oddly enough, it’s called an apical bud. Inside the apical bud is the apical meristem. This is the origin of the whole shoot system. The shoot system is comprised of aerial stems, leaves, and branches and is responsible for stem growth, leaf arrangement, and development of branches. During the primary growth phase its main objective is to add height to the stem so that it can reach adequate light. As the stem develops, it divides into different sections called nodes which appear as little bumps or swellings on the stem near where leaves and branches emerge. Some plants require pruning at the node, so knowing what they are and how to locate them will prove useful.

On either side of the apical bud, lobe formations indicate the first stages of leaf formation. These are called leaf primordia. They offer protection to the meristem from the elements. The true leaves are the second set to emerge and look like miniature versions of the mature leaves. True leaves harvest light as an energy source to create food for the plant through photosynthesis and begin this process as soon as they are exposed to light. They are arranged on the plant in order to receive the most sunlight and air circulation. It is worth noting that the emergence of the true leaves are a sign that it’s time to begin offering the seedlings additional fertilizer. Generally, a 1/4 to 1/2 dilution of fertilizer is recommended. Opinions vary on when it’s the best time for this. Some prefer to wait for the second set of leaves. A good way to decide is by gauging the condition of the cotyledons, the large leaves that emerge first. These are the food stores for the plant and once exhausted of their supply they will begin to turn yellow, shrink, and fall of the plant.

Axillary Bud Primordium also develop at this point and form at the base of each new leaf. These are the beginning of potential branches or flowers. They lie dormant until the plant signals for them to grow in response to changes in environmental conditions and also in response to damage like pruning or wind damage.

Secondary Growth Phase

Once the stem has reached sufficient height the Secondary Growth Phase begins. During this phase, the primary focus is on increasing the girth of the root and stem which occurs through a series of biological processes. The base of the stem and roots thicken to better support the growing plant and its leaf canopy.

In Conclusion

This is a very basic overview of the processes that occur and the plant that develops. It is a very complex and amazing process with more pieces and parts than I can get into in this format. My hope is that by removing some of the bulk, I can truly provide you with an understanding of what is happening when you grow from seed. I have provided a list of suggested reading below and I urge you to dig deeper so that you can have a more meaningful understanding of and connection to all that grows around you within this Kingdom Plantae.

This is the first post in this series, so be sure to check out the next two which include a supply list that can be found here https://youreverydayenrichment.com/guide-to-indoor-seed-starting-the-supply-list/ and planting instructions found here https://youreverydayenrichment.com/guide-to-starting-seeds-indoors-the-instructions/.

Resources:

Pavlis, Robert. Plant Science for Gardeners: Essentials for Growing Better Plants. New Society Publishers, 2022, Hoopla, http://hoopladigital.com/ebook/plant-science-for-gardeners-robert-pavlis/15166868.

-This book provides so much information but breaks it down into small digestible bits. I highly recommend it. There were, admittedly, sections that were way over my level of expertise. For example, there is a section on the importance of knowing the scientific names of plants and I get that….I don’t know them, but I get it. This section develops into naming your own plants but I am still at a level where I name plants things like Edward, Bonnebelle, and Penelope (pronounced Penny low p). 🙂

Capon, Brian. Botany for Gardeners. 3rd ed., Timber Press, 2010, Hoopla, http://hoopladigital.com/botany-for-gardeners-brian-capon/15240271

-This book is great. It has so much useful information. This is the kind of book that a gardener should own for reference. I will be purchasing this one.