seed planting and propagation
seedling propagation
commercial seedlings
There is nothing wrong with using commercially  grown seedlings but they have both advantages and disadvantages over their home grown cousins.

Photo of commercial cabbage seedlings
Cabbage seedling punnets
for sale at a nursery.

Photo of commercial broccoli and carrot seedlings.
Commercial broccoli and carrot seedlings on display.  Note that carrot seedlings are difficult to transplant and I do not recommend you buy seedlings that are difficult to transplant.
easy to grow
As long as you are using seedlings that are easy to transplant commercially grown seedlings are easy to grow.  For a list of seedlings that are easy to transplant see the Seedling Transplant Chart page.  Commercially grown seedlings that are easy to transplant are ideal for beginners.

No waiting time
Commercially grown seedlings can be bought and planted on the same day, whereas if you want to use your own seedlings you have to start growing them at least four weeks ahead of when you want to plant them.

Good as stopgaps
They are also good as stopgaps for when seedlings you are growing yourself are not ready in time.  I rarely get through a season without buying at least one punnet of commercially grown seedlings.

disadvantages of
commercial seedlings
Commercially grown seedlings are much more expensive than buying seeds and growing your own seedlings. You usually only get eight seedlings per punnet and in Australia punnets generally retail for around $3 AUD.

Lack of diversity
If you were to list all the different varieties of vegetables available as seedlings you would only fill a few pages, but if you were list all the different vegetables listed in the various seed catalogues and for sale in nurseries you would end up with a very large book.  Growing your own seedlings opens up a Pandora's box of what can be grown as seedlings.

weak seedlings
Commercial seedlings are grown under ideal conditions with plenty of water, heat and fertiliser to grow them as quickly as possible.  This tends to produce seedlings that are more likely to be stressed when first planted in the garden as they are not used to the tougher conditions.

not as environmentally friendly
Most commercial seedlings are grown hundreds of kilometres from where they are sold and a lot of fuel is used to truck them across the country.  Transporting seeds uses much less fuel.  Also the punnets that they come in are only used once.  If you grow your own seedlings not only will less fuel to be burnt but the punnets and pots used to grow the seedlings can be used over and over again.

Buy local seedlings.
If you have to buy seedlings then try and buy ones that are  grown locally by small operators.  These seedlings are usually tougher than the ones grown by large wholesale nurseries as they are not forced (grown quickly under ideal conditions) and are grown under local conditions.  Local seedling growers can often be found at farmers markets.  Some nurseries and agricultural supply stores also stock local seedlings.  Local seedlings can usually be spotted as they are generally  grown in non standard containers such as styrofoam cups or even just wrapped in paper.  If you are unsure then simply ask the vendor where they were grown.

Do not buy seedlings that have been stressed due to lack of water or being left to grow too big for the punnet.
Seedlings that have dried out at any stage should never be bought as lack of water usually triggers them to go to seed straight away.  By buying and planting them not only will you be wasting your money you will be using up valuable space in the vegetable patch. 

This also apples to seedlings that have grown too large for their punnets.  Some nurseries offer seedlings that have lost condition at discounted prices but don't waste your money on them.  Only buy seedlings in to prime condition.

Do not buy seedlings that are difficult to transplant
Some unscrupulous nurseries sell seedlings that are very difficult to transplant.  For a list of seedlings that are difficult to transplant see the Seedling Transplant Chart page.