How to Grow Plants from Seed
Learning to grow plants from seed is by far the most common way of obtaining new plants. It is also one of the most rewarding. There is just something imminently satisfying about growing a plant that one has started from seed!
Here are some steps to follow when learning to grow plants from seeds.
Obtain Fresh, High Quality Seeds
The older the seeds, the less vigor they usually have. The older the seed, the lower the percentage of germination. Unfortunately, there is no hard and fast rule for how long seeds stay viable. Every species is different.
It also depends upon how the seeds were stored in the first place.
Storage of Seeds
If the seeds were kept cool and dry, then most vegetables will be viable for 3 to 4 years; however, onions and beetroots are usually good for only a couple of years. Tomatoes, capsicum, watermelons, cucumbers, and rockmelon can remain viable for 5 years or more.
Most flower seed can be stored for approximately 3 years under certain conditions. A good rule of thumb is that every 3° C decrease in the storage temperature (all the way down to freezing) can double the storage life of your seed. However, once you get below freezing, it can be a mixed bag, depending on whether the seeds are more native to the tropics than the temperate zone. For that reason, it makes sense not to store seeds in the freezer unless they are native to the temperate zone.
Several experts suggest that gardeners keep their seeds in the refrigerator, and make sure that they are in moisture-proof containers. The moisture-proof part is important, because for every 1% decrease in seed moisture content, seed storage life doubles. Of course, it is possible to avoid the entire issue of seed storage by simply buying no more than you will actually use, but that is easier said than done!
Vegetables are usually easier to start than flowers, partly because so many flowering plants have such small seeds.
Native temperate climate plant seeds (such as wildflowers) often require, or a least do better with, a chilling period that mimics winter enough to break the seeds’ dormancy. Six weeks in temperatures below 5° C usually does the trick.
Quite a few tropical plants have their own set of problems when it comes to growing them from seed. They often have only a short period of viability before they lose their ability to germinate, so getting fresh seed is especially important in such cases. To make the challenge even greater, sometimes tropical plant seeds take months to germinate, or require extremely specific care.
Germinating the Seed
To germinate seeds, you must create the proper environment. A seed starting area can be located anywhere that has moderate temperatures, light, and good ventilation.
Here is a list of what is necessary for good germination.
Disease-free soil and pots
Disease causes poor germination. Diseases can lurk in old, dirty pots. Most gardeners reuse pots, but if you are going to do that, wash them thoroughly with some dish detergent and a little bleach. Old potting soil or garden soil can also host diseases. You can sterilize the soil in your oven before you use it, or you can simply start your seedlings in brand new soil from the store.
Germinating seeds usually require constant moisture
Keep the soil moist but not dripping wet. Don’t let the soil dry out, even once, because that could kill your germinating seedlings. If your tap water is extremely cold, you can hasten germination by using warm water. Gently mist the soil with a spray, much like a light gentle rain, or the seeds might be blasted out altogether. Once they germinate, your seedlings won’t need quite so much water.
Seedlings need air to germinate
Make sure you don’t constantly saturate the soil. Any container in which you start seeds should have a drainage hole in the bottom.
Getting the temperature right
Although plants vary in their temperature requirements, most seeds have trouble germinating when the soil temperature is below 10° C. A temperature of 18° C to 21° C is ideal for germinating most seeds. Heat mats are a good way to warm up the soil without changing the temperature of your entire indoor space.
Getting the light right
While most seeds don’t need light to germinate, some, like lettuce, do. Check the instructions on the seed packet or in the catalogue. Seeds that need light should be planted shallowly, in a well-lit area. Once all seeds have germinated, they will all need light. There are many different setups available for indoor plant lighting, just make sure that the bulbs are full spectrum. For best results, always place the light 5 to 8 centimeters over the soil during germination, then over the emerged plants.
Why depth is important
A good rule of thumb is to place seeds at a depth 2 to 3 times their width. Any deeper, and they may run out of energy before they reach the surface. Be extra careful that seeds you plant shallowly don’t dry out.
The importance of nutrition
Little or no fertilizer is required to germinate seeds. In fact, too much nitrogen can be a major problem in very young plants. When in doubt, leave it out.