This is a really good idea if you don't have a lot of room in your backyard, of if you're like me, aren't the greatest at keeping plants alive. They can be used any time of the year and you can grow almost anything in them. The best use for them is to start seedlings off or like me turn them into herb planters. If you are using it for anything with a complex and large root system keep in mind that they will need to be taken out of the foam box eventually, as they will start to grow through it.
What you will need.
a fairly deep foam box
an extra piece of foam (i got mine from the inside of an appliance)
a hobby knife
White paint (or any colour)
small piece of netting
any seeds you like, i used chives, basil and parsley
Step 1: Foam Box
I got my foam box from my work but they are very easy to come by just ask your local supermarket as they usually have them out the back. The first thing to do is to paint your foam box you can use any paint for this, i have even used house paint and it works fine. This will help keep the shape to the box and it wont break down as fast. You can use any colour you want but i would suggest lighter colours as the sun will reflect off it and it will help to keep the roots and plants cool in summer. After a couple of coats you should feel that is has made the box a lot stronger.
Step 2: Making Legs
I have just recently moved house and so i ended up with a lot of the foam that comes from inside appliances. The one i used is roughly 2 inches thick and because of the shape of it i just cut it into 4 pieces and they were the right size to use as legs. You could just sit the box on top of some bricks or not use legs at all. The only reason i suggest using them is so the box is able to drain more efficiently to prevent root rot and it will also help to keep pests out.
Its a good idea to paint these as well either before attaching them to the box or after, it doesn't really matter. Then use PVA glue to attach the legs to the bottom of the box. After a few minutes turn the box upside down(so its the right way up) and place something heavy(ie. books) inside to weigh it down.Leave it over night to dry.
Step 3: Preparing the Box
You will then need to cut 6 holes in the bottom of the planter so that any excess water can drain out. I just used a hobby knife to cut them but any other knife will do but please just be careful. It doesn't matter where theses holes go but three down either side works well. Next you will need to cover the holes enough so that water can still drain out but the soil wont be able to fall through. Most people suggest to put stones in the bottom but i find that this covers the holes up too much so you could either use pieces of a broken pot to create a bridge over the top, or you can do what i do and use netting. I just had some left over netting from a tutu i made so i used that. You will need to stick the pieces down so that when you put the soil in they wont move. Just use a little PVA glue to keep them held down. This will only need to dry for a few minutes. You don't need to cover the holes but it will prevent slugs and other bugs from getting in your planter.
Step 4: Filling Up the Box
Fill up the box with potting mix until roughly an inch from the top and if you wish mix some manure with the mix. Leaving the inch at the top will be really helpful if you are starting with seeds as it will act as a bit of a barrier to wind. I planted chive and parsley seeds in mine and i had some basil seedlings that i transferred in there too. And thats pretty much it. now you jusdt have to wait for it all to start growning
Step 5: The End
So this is my basil seedlings after about a month. Unfortunately becasue of the weather here the chives never did grow as it was too hot and the parsley at this stage hadent started growing, i think that was due to the weather too.