The idea with straw bale gardening is to build up the nutrition of the bales by initially watering them with high nitrogen. The water and the nitrogen start a reaction where the bales begin to compost and they grow warm inside. At this point after about two weeks you can start planting things into them, either small seedlings, established plants or even seeds. The bales retain moisture in their insides and gradually release the nitrogen and any other feed that you put in to the plants.
It so happened that we had in our very useful barn a whole load of double glazed window units. I arranged these around the bales to minimise moisture loss from the bales, give some protection from the wind for small seedlings and provide a temporary glasshouse for them. Over two weeks I sprinkled nitrogenous lawn feed, organic chicken manure, blood fish and bone meal and buckets of our own urine onto the bales. They soon grew warm to the touch and with their own delicate aroma.
Over the two weeks it took for the bails to start warming I was also raising seeds. I grew tomatoes and aubergine’s, cucumbers and courgettes, squashes and even loofah plants. In my cold frame, made from a bit of tongue and groove and a friends old shower unit, I had lots of mixed salad underway with spring onions, what turned out to be masses of spinach, Basil aplenty, one of my favourite summer herbs, along with my favourite flower, English pot marigolds.
Soon the planting began. Areas of shade were to grow leafy plants such as salads and spinach. Also a row of peas and some dwarf beans. I checked out my companion planting chart and transferred oregano plants to the straw bale that was to grow purple sprouting broccoli and cauliflowers. I had also put some giant onions into pots to stimulate their root growth. These were ideal packed in to the small spaces that had formed in between the bails. Once my tiny seedlings had been potted-on I bought them outside to place on the bails as they benefit from the warmth coming from the bales underneath whilst they hardened off in the early spring air.