Last week I took up the discussion of why we would want to grow vegetables from seeds instead of from nursery starts. And as it turns out, there are tons reasons why choosing seeds can be even better than starts. If you missed last week’s post, check out “Part 1: Why Grow Seeds?” to get in the mood.
This week I am going to offer some clear and simple guidelines for planting your seeds that will assure their success. Even home vegetable gardeners who know which seeds to plant, often miss some important step in the planting process and are understandably frustrated with the results. If you follow these simple steps, your seeds will grow healthy, happy, and strong in your garden.
The THREE MOST IMPORTANT THINGS to think about when planting seeds are: Planting depth, seed spacing, and watering method.
Each seed is a tiny little package imbued with incredible potential to become food on our tables. But it is only with our care and nurturing that such a tiny thing can achieve such a feat! It is the stored energy in a seed, activated by moisture and temperature, that sends the first feeble leaves upwards to seek the light of the sun. The smaller the seed is, the less energy it has stored for that first burst of growth.
It is because of this fragility that planting depth is such an important consideration when sowing seeds. If a seed is planted too deep, it doesn’t have enough energy to send up its first leaves and may die before ever seeing the light of day! On the other hand, a seed that is planted too shallowly can be displaced by watering or rain, can be eaten by birds or rodents, or may dry up with exposure and never germinate.
So it follows logically that smaller seeds should be planted more shallowly while larger seeds should be planted slightly deeper. A good rule of thumb for planting depth is to plant seeds as deep as 3-4x their width. For large seeds like some beans, which might measure ½” across, this could be as deep as 2", while for the tiniest of seeds like carrots, or turnips, this might mean just 1/4"-1/2" deep!! Finding the right balance is key, and following this simple rule will help.
The space between seeds is another area where even experienced gardeners often go astray. When spacing seeds, you should first imagine the mature size of the vegetable that you are planting. In order to maximize the use of your space, you should strive to have mature vegetables that are close together, but not so close that no individual can mature properly. When seeds are spaced too close together, sometimes none of the seeds that are planted can grow well, and the planting may never be harvestable. When seeds are too far apart, they have too much room to grow. This is only a problem in that garden space is not used efficiently and yields will be lower.
The most sensitive of seeds when it come to spacing are root vegetables. Sensitive taproots like carrots begin to swell later in their life cycle. If they encounter physical obstacles, whether other roots or weeds during this critical life stage, they can become permanently stunted and never make carrots!
As a rule of thumb for spacing on root crops, space them at twice the density of their mature width. For a carrot, which might have a mature diameter of 1", space seeds at 1/2". This will account for some natural losses from seeds that don't germinate, and will also allow them to cozy up to each other and maximize your harvest. If you sow your seeds at a higher rate than intended, just remember to "thin" them after they germinate leaving the intended spacing between each plant. "Thinning" refers to the culling or removal of some of your germinated planting in order to accommodate future growth.
Greens like lettuce, spinach, and arugula are less sensitive to spacing considerations. Greens that are planted at a high density (¼” spacing) can be harvested with scissors as “baby” greens, while greens at lower density (1” spacing) can be harvested when larger and more mature like head lettuce. As long as you keep the future of your seeds in mind and plan accordingly, they will be happy in your garden with the proper spacing.
So your seeds are perfectly spaced at their proper depth and ready to grow. What could possibly go wrong? Well… A lot.
Even if you do everything right up to this point, it can all be undone in a single watering. For watering "seedbeds," that is areas that have been sown with seed, but have not yet germinated, it is essential to use a gentle watering method. I prefer to use a watering can which can deliver a delicate and gentle shower. A gentle hose attachment is second best, and watering straight from the hose is a big no-no! Watering with more aggressive methods will displace the tiny seeds you have so carefully placed scattering them in all directions. And most seeds are so small that you will not even know the destruction you have caused!
Use a gentle method taking several shallow passes over each row, allowing water to percolate evenly to the depth of your seeds, and never allowing pooling. If it is a rainy stretch of our Oregon spring, you may not need to water more than a single time, but if weather is sunny and dry make sure you water every couple of days in cool weather, and every day in the heat of the summer to keep the soil surface moist. This is the most delicate time in the life of your vegetables and if seeds dry out before they germinate they can die an early death. Once your seeds have germinated and found their way to the surface, they will have slightly decreased water needs going forward, but until germination, it is very important that your seeds don't dry out!
If you follow these three principles remembering proper spacing, ideal seed depth, and appropriate watering method, your seeds will thrive! You will find that growing things from seed opens up a whole world of possibilities for you as a home vegetable gardener. It is an essential skill, and of course, it is a pleasure, bringing more in the way of what you want from your edible garden.