[michellela]

Earlier in the year before I had a plot I spent lots of money on compost to plant toms and carrots on my balcony.  When I got my plot I went and got more compost as I don't have my own composting system yet.  Next year I plan to start off some parsnips either indoors or on the balcony, planting them in paper pots, so my question is this... how comes I can't just sift some soil from my allotment and use that instead of continually spending money on compost?

[paintedlady]

when starting off seeds, it is probably cost effective in the long run to provide a growing media where they will thrive in the first few weeks until they get planted out - there's nothing worse than seeing newly germinated plants fail to grow, and compost contains nitrogen which is essential for growth.  Don't forget, pots of soil/compost will have finite nutrients "diluted" down with sand grains, and who knows what pests (microscopic or eggs) & diseases lurk in the soil which seedlings are perhaps more vulnerable to.  Even when sowed direct on the plot, I make a drill and fill with a little layer of compost to give the seedlings a boost until their roots & foliage become established and better able to grow in the allotment soil.

[gillie]

There are two meanings to the word 'compost'.  One is the stuff you get from rotting down vegetable matter in a systematic manner.  This is highly nutritious but heaving with all kinds of life forms.

The other is what you get in bags from garden centres with labels such as 'multi purpose' or 'John Innes'.  This is a pretty much sterile mix of fibrous matter and fertiliser designed to give plants an ideal growing medium.  This is what you use to start seeds.  

In 'the olden days' gardeners did make their own seed composts from soil, their home made compost and fertiliser but they had to sterilise it using contraptions for passing steam through it and the quality must have been very variable.  Bought in composts are much easier and more effective.

Like Paintedlady I line drills before sowing seeds, and also cover the seeds with bought compost to give them a good start.  For parsnips I usually make a deep hole with a stick wriggled round, fill it with compost, sow two or three parsnip seeds and top it off with more compost.

[savbo]

Don't know how much soil you were thinking of taking home but our allotment rules forbid us from taking any soil from the site...

[michellela]

Thank you for the replies.  Using shop bought compost seems to be the best way to go as I have no desire to try steaming my own.  I guess the idea was a non-starter really as I don't plan on hefting a lot of soil from plot to flat but I was curious and you've all helped me figure it out.  Thanks!