It was inevitable. It’s the pride before a fall. At first you have the excitement of seeing the mass of green seedlings appear and then you notice that some have gone limp and then disappear.  The next day the patch of dead seedlings has expanded and, before you know it, they are all dead. It can happen in as little as a few days and it hurts!

Damping off is caused by a soil fungus. It is why it is important to use clean pots and trays for sowing, and fresh compost. It is encouraged by cold, wet conditions and is very common with early sowings and some seeds are more prone to the problem than others. Antirrhinums are classic sufferers. Whether this is because they are usually sown early or whether they are just more prone I do not know but I do know that when I worked on a commercial nursery we more or less watered them with fungicide. I am going to blame this disaster on the compost because I had mixed some pretty awful John Innes with the multipurpose for the cabbages and onions and I think this may not have been very sterile. Anyway, once you have it in the seed tray you have a real problem. The fungus spreads along the soil surface, invading the seedlings at ground level, and toppling them. As the fungus spreads out it makes an ever-increasing patch of death, rather like a fairy ring in the lawn. You need to transplant your seedlings as quickly as possible to get them out of harm’s way but it is important to realise that the fungus has spread beyond the visible spread of the disease so you will have to discard those seedlings next to the dead area.

Now the observant will look at this photo and tut and say ‘well he was asking for trouble – look how thickly he sowed those seeds.’ And they would be right. Sowing thinly will often ease the situation because if the seedlings are sparse the fungus runs out of ‘victims’ and will not spread. So my excuse? Well it was simply that these were seeds saved from plants last year and I have loads of them. They were stored in an envelope in an area that I thought was safe but it got damp and I was sure that they would not grow so I sowed a bit thicker than I would normally. Anyway, the good news is that I sowed them over a six-cell tray so the attack was confined to one of the cells so I was able to transplant a batch of 350. It is almost impossible to transplant these tiny seedlings singly so I try to transplant little clusters of two or three. When or if they all grow I will pinch off the spares to leave one per cell. If you are growing a mix of colours it is important that you do not pinch off the weaker and leave the strongest because often the weakest plants at the seedling stage have the best colours. As these were from my own saved seeds of ‘Constantine’ I grew last year and I saved seeds of the pinks and the darkest leaves I will remove the plants with the lightest foliage colour – which does not show up at this tiny stage.

You can sometimes reduce damping off with an application of Cheshunt compound or other copper-based fungicide but as it has to be applied as a liquid and overwatering is a contributing factor it is not 100%. I try to keep the seedlings moist but not wet but it is a fine balancing act.

cheshunt compound, damping off, seedlings, Sowing, sowing seeds