By Olivia Chipeta Nkolokosa
This week, if you have noticed, its been very cold in most of the places in Malawi and growth of plants has slowed down for most plants. This is so, as low temperatures lower rate of activities in plants just as it is to humans. The enzymes normally work effectively when temperatures have reached a certain temperature. As a result of this chilling weather, germination of some crops becomes a problem. Some vegetable plants however, just have this tendency of being difficult to germinate. We will look at some ideas of how we can induce quick germination.
The easiest and conventional way of inducing roosting and germination in some vegetable seeds is through immersing in room temperature water. You soak the seeds in water for few hours to 24 hours so that the seed can imbibe some water. One of the key elements in germination is that the seed should have absorbed adequate water. Some seeds have hard seed coats (cover) such that it takes time for the water to be absorbed.
As a result soaking the seed facilitate adequate time that the embryo should absorb as much water as possible, hence germination takes a short period. Seeds like okra, green pepper can use this method. Some require warm water to enhance germination.
Another way is to scratch or prick the seeds. Some seeds like fruit seeds of peach, plums, baobab, have hard seed coats that are difficult to absorb water. Providing some pressure in form of a scratch that sheds off the hard seed coat provides an easy way for absorption of water thereby enhancing germination. Some like Baobab do well if one combines soaking, scratching then peeling some seed coat. Pricking or nicking the seed using a sharp needle also provides a way of quick germination as the water goes directly to the embryo.
In order to break dormancy in some seeds, chilling temperatures also provide a way of speeding up the germination. For example, if you remove the peach seeds, wash them, they can be soaked in water then placed under chilling temperatures (refrigerator) in a jar with moist soil. Germination will.be quicker than anticipated.
Some crops like lettuce like warm environment for germination to occur faster so these temperatures should be provided. A good example is the use of the plastic mulch in winter periods. The transparent plastic mulch will enhance germination as it also provides direct light to the seeds apart from the warm temperatures. This is so as seeds primarily require moisture, warmth and air for germination. Other factors are secondary at this stage. Therefore exposing your seeds like tomato, peppers in a warm moist conditions with or without soils increases their rate of germination in terms of time and quantities.
Artificial hormones working as Gibberellic acid also facilitate smooth germination as they help in breaking dormancy. Sometimes seed cannot be in an active state that it is ready to germinate due to the hormones that are at work at that particular time. Inducing the plant with some artificial hormones assist that the dormancy should be broken down hence activate the germination process. We will be looking at some principles in actual management of some common horticultural crops in the next segments.
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.