Of course using seeds is a lot of the time preferable. It’s usually the easiest, simplest and most economical process among these and since it is sexual reproduction (two plants breeding together) it leads to stronger, and more disease resistant plants. This is the only propagating process that leads to genetically different offspring and more genetic diversity. This can be an advantage for evolution purposes and survival or a disadvantage because you can’t get the same plant that you seeded unless you make it self-pollinate (and some plants can’t do this). Seeds also take a long time to turn into a mature plant in some cases. There are also plants that don’t even produce seeds or if they do, they produce non-viable seeds. Most of the plants I’ve dealt with from tomatoes to watermelon to basil are produced by seed and have many different varieties to choose from.
The other option is asexual reproduction (or vegetative reproduction) which is when a single parent gives rise to an offspring. This can be through vegetative parts such as tubers, bulbs, roots, stems, leaves etc. There is no exchange in genetic information and thus the offspring is exactly the same as the parent – which can be a good thing for the gardener or producer. Other advanced propagation techniques which I might develop into in further years are layering, grafting and budding.
Below are also onions and garlic which are produced by bulbs. The bulb is also a modified stem and the layers are actually thickened leaves for food storage. The green leaves you see above ground are its photosynthetic aerial leaves. The individual garlic cloves are actually multiple stems that can be separated and planted individually.
The weird looking forked thing alongside the greyish stringy root thing are actually a rhubarb and asparagus crown. The crown is just the part of the plant where the stem and the root join together just below the soil. These two plants are reproduced artificially and asexually by divisioning an existing plant into different parts and taking a part of the crown with it.
Also off topic but since I’m talking about different planting techqniques, my strawberries, raspberries and blackberries will also be planted this year with two different methods. The first is the bare root method. This is the much cheaper option and all that you are given is a dormant root with a bit of dormant shoot. The first season planted in the ground is used for producing above ground shoots and plant establishment while fruit is only produced in the second or later years. The other option is purchasing a potted, already established older plant. This may be the more expensive option, but if you’re impatient, you can get fruit within the season that you plant.