If you're like me, you end up using dozens if not hundreds of little seed pots every year as you sow your seeds, prick out your seedlings and grow subsequently them on. Traditionally I have always used the plastic pots, but as a responsible gardener, I questioned whether I should be using biodegradable versions instead as they generally become more popular - but are they any good?
So last year, I tested biodegradable ones for the first time, using Gardman Fibre Pots. It's fair to say that both the plastic pots and the fibre pots have pros and cons to them and usage will be personal choice, but here are my thoughts:
We don't currently sell the plastic variety of seed pots, but a quick search online finds we can get 50 x 9cm pots for around £5.60 including postage, so about 11p per pot. In our online store, you can buy 96 x 6cm fibre pots for £12.95 (13.5p per pot) or 48 of the larger 8cm fibre pots for £9.99 (20p per pot). So, clearly the plastic pots are the cheapest option.
By the nature of most types of biodegradable pots, they are only used once - as you're planting the whole pot in the ground and allow them to rot down. However, the plastic pots can be used again and again if cared for properly. So in terms of cost and cost per use, the plastic pot is a clear winner.
Although I've found it hard to find any tangible figures about the environmental impact on producing plastic versus fibre pots, the general consensus is that the production of fibre pots has a lower environmental impact in terms of lower energy usage to manufacture, materials used and overall carbon footprint. Also, when it comes to disposal, you either end up with a pile of them in your garden, or thousands (if not millions) of plastic pots are sent to landfill, taking many, many years to rot down and having a far greater environmental impact than the fibre pots. However, the flip side of this is that the plastic pots can be used time and time again. When they are used and re-used numerous times, it could be suggested that the plastic pots could actually be considered the more environmentally sound option in the longer run, although at the end of their life when they crack & break, the landfill disposal problem still exists.
Ease of Use
For me, this is where the biodegradable pots have a distinct advantage, being an out & out time saver. When you're growing seeds and seedlings in any great quantity, the time required to pot-on seedlings between different sized pots can take forever - easing the seedling out of the pot, transplanting it to the new pot and all the time taking care not to damage the seedling or the roots. However, with the fibre pots, you don't need to worry about doing this, simply plant the whole pot on. Similarly, when it comes to planting out the plant, you don't have to waste time taking the plant out of the pot, simply pop the whole pot into the ground and away you go.
One of the arguments put forward in favour of using fibre pots is that you avoid root damage which can be incurred when transplanting seedlings and young plants. However, my concern was whether the roots of the young plants would be strong enough to push through the sides of the fibre pots and would they rot down quick enough to avoid holding back the growth of the plant. I needn't have worried - the plants grown in the fibre pots were just as good as the ones grown in the plastic pots. When I dug out a couple from the ground, it was clear that the pots were rotting down after just a couple of weeks and the roots were growing unencumbered just as though the pot wasn't there.
Overall it's clear that there isn't one option clearly better than the other. If cost or cost per use is your priority, then the plastic pots are clearly the ones for you. If being environmentally friendly is important to you, then it can be argued that the plastic pots could have the edge if you're going to make sure you use them time after time. Although the important issue of disposal in landfill of the plastic still remains however many times you re-use them. The big winning point for the fibre pots is how easy they are to use and how much time they save you when you are growing seedlings in any quantity. And at the very end, as far as my tests have shown, there's no difference in the quality of the final plant whether you use the plastic or the fibre pots.
So what will I be doing? Well in the first instance, I'll continue using the plastic pots I already have until the reached the end of their useful life. However, as and when I need new pots, I'll be migrating over the the biodegradable variety.
Do you have a preference? Let us know.