With wet weather affecting potato growing regions in mid-March, planting looks as if it will be delayed for a little longer until soil conditions come right. Seed management and storage could start to become a problem on some farms.
It is important seed is checked over as soon as it comes on to the farm - any issues identified need addressing as soon as possible with the merchant.
Opening the bags and checking for rots and looking for obvious signs of chitting in the bags are the first things to look for, as this may show if they got too warm in storage or transport.
Washing about 100 tubers and looking for tuber diseases – ideally with a USB microscope - can be done very quickly and effectively. Also cut through them and look for any internal issues. With modern smart phones it is easy to keep pictorial records of seed lots, with photographs of any issue for the farm records.
This also allows for general good practice of checking back which seed batches performed best. All of these activities should be done before the seed is boxed.
Chitted seed can become a bit ‘frothy’ if left in the warm and the light longer than intended. The chits get too long and break easily at planting, so it is important to monitor chitting houses and move seed around if required.
Depending on variety, there is a huge range of speed of development of chits under the same conditions - so treat each batch differently.
It is not uncommon to see the hopper on the planter full of chits at the end of each day and that is before the tubers have even got to the business end of the planter. Belt planters can handle these longer chits a bit gentler, but cups can knock most of them off.
Planting seed with long chits which then get ‘knocked off’ can lead to several issues. There has been a lot of research done over the years looking at the effect on yield and tuber size distribution where chits have been lost – and it is not a great start for the crop.
Seed tubers use a lot of energy to grow chits, and knocking these off is considerably worse for the potato plant than never having chitted them at all - and it is a waste of time and money. It can also lead to poor emergence, especially where seed is planted into cool, wet soils, and result in severe blackleg infections later on.
Seed dressings and soil applied fungicides can all exacerbate these issues in ‘de-chitted potatoes’, so careful monitoring is essential to ensure seed tubers have chits which are small and green and strong when they go in the planter.
Even where seed is not being chitted it is important to monitor it before planting. Keeping air moving around the boxes so the seed doesn’t start to sweat and break down is key.
It is no different to storing a ware crop in reality, and when we are getting pushed for time and space it can be tempting just to leave the seed in the big bags it is delivered in - but this is not good practise.
Where space and boxes are getting tight it is important to remember not to let anything contaminated with CIPC be used for seed storage. CIPC leaches out of the boxes and walls and floors of the store and this too can affect speed and quality of emergence.
When planting does finally start to get close then reach for the spade. It will be essential to check soil conditions and ensure the machines are not working in that ‘plasticine’ layer.