Gardening: Growing tomatoes on bales of damp straw

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At RHS Garden Harlow Carr we have definitely made full use of the greenhouse in the Kitchen Garden training vine tomatoes and cucumbers up the wall. Every other space is taken up with peppers, chillies, aubergines, tomatillos and lots of highly scented herbs.

This year we have tried a different technique to usual and grow the tomato plants in a slow decomposing bale of straw.

The bales are thoroughly wetted and fermentation is triggered by adding nitrogen, thus building up heat and giving off carbon dioxide, which is also beneficial to young plants.

The bale should stay damp. After three days of watering add a fertiliser such as a blood meal and then again thoroughly water to let the nutrients absorb.

The straw will heat up as it decomposes and should reach 43°C -54°C. Keep checking the temperature every few days. When the temperature drops below 38°C the planting can take place.

The bales should be ready for planting three to four weeks after the first watering began. On each bale you should be able to grow three to four plants. Put a couple of handfuls of compost on top of the bale and place the plants deeply into this. Tomatoes have tiny hairs on their stems called adventitious roots, which is the start of root formation. Planting deeply means the plants will produce more roots which will help to improve the plant’s root structure.

Feeding is essential as the bales do not provide the nutrients that the plants needs to grow, so just like growing tomatoes in the soil, feed with a high-potash fertiliser every couple of weeks once the flowers have formed the fruits. Keep the bales moist by watering them daily and don’t let them dry out.

If you are growing the vine variety of tomatoes and not the bush varieties, supports will be needed.

String or bamboo canes can be used. Just make sure the supports are strong enough to carry the weight of the plants. Always check every week to see if the plants still have room to grow where you have tied them onto the supports.

Not only tomatoes can be grown on the bales, cucumbers, pumpkins, peppers and squashes also do well.

Tomatoes can also be grown in containers or grow bags, sometimes with a plastic pot with the bottom cut out to create extra depth. This sits on the grow bag, which allows the tomatoes to be planted deeper and helps keep the soil moist.

Advantages of growing on straw bales are; no digging or soil preparation is required, the bales can be placed on your driveway if you have no other space or soil in your garden, and used bales can be recycled and put on the compost heap once you are finished growing your tomatoes.

I think they also ripen much faster than tomatoes planted into the soil.

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