By Olivia Nkolokosa
Article number 6
Having looked at some principles in farming; it is important that we also look into some of the points we should always put into mind when we have down our crop. Most vegetable seeds are very tiny, very difficult to handle to be sown independently as a result, their sowing depth and coverage is directly related to seed size. If you are planting a mango seed, the sowing depth is relatively larger than when sowing carrots. The coverage (soil) will also be heavier than the seeds of carrot. When you plant green peppers, your treatment of the seed will be different than when you plant cassava.
Some of the reasons why seed will not germinate come from management aspects s whilst others are more physiological. Let me put it this way, you may plant a certified seed that cannot fail to germinate but you find that it has failed to germinate. You will have several factors that you will think around.
First it could be that you have been watering too much or not enough, likely too much. Each crop has specific water requirements at each stage. Seeds do not require a lot of water so are seedlings. Germination occurs when the seed has absorbed the required water, excess makes it just to rot. Therefore, your seed will not germinate. When you check the seed beneath the soil, you will find it there with some pieces rotten. Sometimes the water may not just be enough for germination to be stimulated. It is important that we know how much we are watering.
Secondly, the seed may not germinate because of the type of soil and covering material. Heavy clay soils are not ideal for some vegetables like Irish potatoes for germination to occur. This is because they hold too much water as such the tuber does not have adequate room for aeration. As a result, the tuber will rot. It is therefore important to know what type of soils our crop will be able to germinate without problems. Covering the so with sand after planting makes it easier for the seed to erupt from the soil than the actual heavy soil because it makes penetration for emergence cumbersome. If you are planting heavy clay soils, use light soil materials for covering such as sand for easy emergence of the seed.
Physiologically, there are problems to do with when the seed was harvested. For a seed to be called a seed, it requires that it reaches its physiological state of that. Sometimes seed can be harvested earlier than the physiological state as a result, when you plant it it cannot germinate. This is why it is advisable to use certified seed for it goes through all the processes of supervision before marketing. Storage also plays a big role in as far as germination is concerned. If your seed is not well stored, it may lose its viability and therefore will not germinate. This is why certified seed is well packaged and labelled. If you store your seed where there is access of water/ vapour, some seed will lose value because they begin the process of germination. Therefore, store your see under good conditions. Check also the expiry date as some seeds may be expired.
Lastly, it may not just be the time for the seed to germinate. Each crop has its germination period, some take 7 days others longer or shorter depending on several factors. It is imperative that you as a grower knows how long the seed takes to germinate. Some seeds require treatment before planting out so that the seedcoat should be moist and be able to absorb water. This makes germination easier or fast. It is important to know your seed.
Olivia Chipeta Nkolokosa holds a BSc in Horticulture from Malawi, MSc Plant Breeding from South Africa. She writes in her personal capacity as an Agronomist.
