Starting plants from seeds can be very rewarding or... very frustrating. Many of the problems can be easily solved, and if you're reading this before you start, you can prevent them. Some seeds are picky, they need certain conditions to germinate, and if you don't provide them, they will sit there, waiting for the right conditions. This can sometimes be good because it allows you to correct the issue and give those seeds a second chance.
Other seeds are more forgiving and will germinate even though conditions are not perfect. Before starting to plant them, read the package information. This blog will address the issues at the start of the process, from planting until the true leaves appear. The first set of leaves that come out are called cotyledons and the second pair are the true leaves.
Problem: Seeds Don't Germinate
There are many causes for this. First, be sure that seeds are relatively new. The longer you have the seed packages, the lower the germination rate. Meaning you will need to plant more seeds to get some of them to germinate (it's OK to plant 2-3 seeds per pot). Another issue is too much or too little (water, temperature, and/or light). Check the instructions and follow them.
Add a heat mat. Keep in mind that most seeds need soil temperature between 60 F and 86 F (20ºC - 30ºC). Note that soil temperature may not be the same as room temperature. Just be sure to turn off or remove the heating mat once the seedlings poke through the soil. Watering with sun-warmed water can also encourage the seeds to germinate faster.
Some seeds need light to germinate (such as begonias), while others must be covered in completely dark. Provide them with exactly what they need, and they will grow. Remember to check the germination days, as they need more time than you originally thought.
Water and medium are also important. Water is tricky. They need a moist environment but not too wet which can spoil the seeds. They also need humidity, so check your soil temperature and water if there are no water drops on the dome. The balance is delicate because too much water will develop fungi in the soil! Our advice is to add water slowly; a little every day is better than once a week when it comes to seedlings.
Problem: Seeds Are Weak and Leggy
This is super easy to fix. The seeds need more light, so they are stretching to get closer to the light source. Seeds need between 14-16 hours of light. Because this is very difficult to achieve in winter, the best alternative is to buy grow lights and place them 2 inches over the seedlings. You will need to move them up as the plants grow.
If you add grow lights, use a timer to ensure they always get the right amount of light. I know it may be tempting to leave the lights on all day, but we strongly advise you not to. The plants will not grow faster doing this, and you can actually hurt the plants as they will not have time to rest.
Problem: Mold Growing On The Trays
This is usually a sign of too much humidity; in some cases, you could save the seeds. If you notice this early enough, remove the mold gently (and take some growing medium with it). Sprinkle some cinnamon on top and add air circulation to dry the area.
There are two ways to improve air circulation. If the seeds are inside the dome, open it a bit, allowing some air in. Or if the seedlings are already in an open tray, put a small fan next to it. Avoid overwatering and watch the humidity level of the germination tray.
Problem: Leaf Curl Or Yellow Leaves
Seeds don't need fertilizer during germination. They only need a good growing medium, light, and the right temperature. Notice that I said growing medium and not soil. Seeds starting indoors must be planted in soilless soil or seed-starting mix.
Gary Heilig, from the Michigan State University Extension, explains, "soilless seed-starting mixes have a finer texture and are made from ingredients such as milled peat moss, perlite, coconut coir fibre and vermiculite."
Many seeds that we start indoors are susceptible to disease, and "since most of these diseases are soilborne, the best way to keep young seedlings healthy is to use" a controlled medium, writes E. Smith on The Vegetable Gardener's Bible book.
The best solution for these problems is not to add fertilizer; if you already did, you may be able to save them. Without adding more, let the plant grow. You will often lose that first leaf, but the plant will grow new ones.
So, when is it time to add fertilizer or soil amendment? We don't think you need them if you use high-quality soil. The microorganisms there will provide all the nutrients for the plant. If you need it, add it only after moving the plant from the small seedling pot to a bigger one. After a few days, the true leaves will be established. When you transplant the seedling to a larger pot (the size of a plastic cup), use potting soil.
Starting seedlings is rewarding, don't be afraid to fail. If you do, you can start new seeds and try again. Gardeners learn from their mistakes, even if they kill a plant or two on the way! Before you leave, check this blog on six basic steps to grow a vegetable garden.