Seed starting is fairly easy, given the right set-up, a bit of patience, and a bit of diligence. Before I get into the right set-up, I want to discuss the wrong one. The wrong one is any set-up that starts seeds in front of a window in northeast Ohio in March. Just as a person may respond to this winter overcast with seasonal depression, a plant will respond to these low levels of light by becoming “leggy.” Leggy can be characterized as plants exhibiting pale, weak, small-leafed, tall growth, where the plant stretches in search of more light. Often these frail plants are so weak that they can’t even be handled, let alone transplanted.
So, what is needed to start some seeds?
Containers with lids
Store bought soil is most often peat moss based. It is amended with lime to buffer the pH and perlite for porosity. Every once in a while it comes with fertilizer. I try to avoid the pre-fertilized soil as much as possible because it’s rarely organic, and it may be too much fertilizer for young plants, which means it can burn (kill) young plants.
The soil serves multiple purposes. In terms of seed starting, the soil holds the moisture necessary to start the seeds. Additionally after sprouting, the soil is a place for the roots to grow and acts as a bank for nutrients.
Now that you have your soil, you need a place to put it. The classic starting tray is 10” X 20” in size and made out of black plastic. These aren’t necessary but are recommended for the sake of uniformity. Within that tray, you place a cell plug tray. The cell plugs come in varying hole sizes, ranging from 72 to 200 holes per cell plug tray. The cell plug tray actually holds the soil and the seed. To accompany the trays, you will also want a clear plastic lid. These are formally called humidity domes, and as the name implies they hold in humidity.
All of these trays are industry standard, but anything that can hold water, soil, and humidity will work. For instance, a flat Chinese take-out container can be used as a tray, coupled with yogurt containers as “cells,” and then topped with the take-out container’s lid as a humidity dome. This is not very uniform, but will work in a pinch or for small scale starting.
A heat mat is essential for starting seeds because seeds like it warm to sprout. 80 degrees is just about perfect for most plants. Basically, a heat mat is a flat electric plastic mat with a cord on which the seed starting trays sit. Heat mats come in one, two, or four-tray sizes. When they are plugged in, they become moderately warm to the touch. It is this warmth that helps your seeds sprout. When a heat mat is not being used to start seeds, some homesteader types use them for making kombucha and kefir.
To bring this essay full circle, an adequate light source is necessary for healthy growth. The old standard four foot long, fluorescent shop light works well, especially when coupled with a four foot shelf and a four-tray sized heat mat. I am personally a big fan of the 150 watt equivalent compact fluorescent light with a few these ran per shelf. The benefit that I see is they provide good light, and they can be turned on and off as needed. Growers have also had success with the new LEDs that emit in blue and red, but this new technology is expensive. The metal halides and high pressure sodiums work better for established seedlings and are not recommended for new starts because these lights are so strong they can physically burn the plants.
Seeds need moisture to sprout. When working with heat mats and lights, the soil has a tendency to become dry. This is where a hand sprayer becomes a necessary tool for the seed starter. When starting seeds, you should expect to spray the trays several times a day in order to keep those seeds hydrated. In conjunction with spraying, the lids should be removed and the water sticking to the top should be discarded. This may seem counterintuitive, but there is a fine balance between wet enough and too wet.
Now that the lights, heat mat, trays, soil, and hand sprayer have been gathered, the only need left is a place to put all this stuff. Almost any place in the house can work, but due to the possibility of dirt and water damage, growers typically get relegated to the basement or washroom. A 4’ X 2’ stainless steel shelf is very common amongst growers. Each shelf can hold a four-tray mat and a four foot light. So in terms of ease of use and uniformity, these shelves seem like they are made for seed starting. However, any set up can work given some creativity and a can do spirit.
From this point, it’s just a matter of filling the plug trays with moistened soil, seeding the seeds, and putting the trays on top of heat mats with their humidity domes. Here’s where the patience comes into play. Seeds germinate at different rates. Kales, arugula, and beets can sprout in as early as three days. Tomatoes are more like five to seven days. Peppers take a little while longer at seven to 10 days, while ground cherries can take as long as 15 days. During this entire timeframe, you will need to take the lids on and off in order to spray those trays with the hand sprayer. This is where diligence plays an important part in seed starting as it’s easy to get bored, or give up, or go away for a weekend.
Overall, this should be enough to get folks started on seed starting. Over time, people generally figure out their own best system. Additionally, each plant is a little different in terms of exact optimum temperature, seed planting depth, and miscellaneous details. One of those details that should be noted is tomatoes like to initially germinate in the dark and then be immediately moved to a light source after sprouting. For all the miscellaneous details, Johnny’s Seeds is an amazing Internet and seed resource. Under every vegetable, they list “growing information.” Their methods are tried and true. You can rely on their details with confidence, which isn’t necessarily the case with the rest of the Web.
Getting Seeds Started Right
Examples of local Cleveland farmers' germination stations: