You might be familiar with terms such as bolting or cutting as it relates to horticulture, but what about apical dominance or GDD? We’re breaking down some common, and maybe uncommon terminology we think you should know.

1. Bolting – Bolting is essentially the premature production of a flowering stem. This situation can be caused by several stress events, such as heat, low or high nutrient levels, changes in day length and/or lack of water. One of the interesting things about bolting is the change from vegetative tissue to flowering tissue. In lettuce you will see the plants dramatically get taller in height and usually a change in flavor also occurs. Once the initial signal or stress occurs to initiate bolting, the plant will not revert back to the vegetative phase, even if the reproductive stem is removed.
   
    
2. Cuttings – Cuttings are used in the process of multiplying and growing new plants from tissue collect from the host plant (this is the cutting). This is often referred to vegetative reproduction or asexual propagation. Often roots, stems, or leaves are selected for this task. There are multiple techniques to collect this plant material which we will cover in more detail in a future post.
   
    
3. Apical Dominance – Apical Dominance is thought of as the control of vertical growth over lateral growth, caused by the hormonal signal from the terminal bud (or shoot apex). In plain terms, the top or terminal bud produces a hormone that sends a signal to the other buds below it, keeping them from growing. If the terminal bud is removed and the signal is no longer present, the lateral shoots will typically begin to grow.  A good example of this occurs when the main growing point is removed from Basil and the lateral buds start to grow, causing branching to occur.
   
    
4. Day Length – In horticulture, day length is referred to as the amount of dark period a plant needs to initiate reproductive growth. Almost all plants need a dark period required for growth. This is where the commonly related terms occur:
   • Short Day Plants- These types of plants flower when exposed to long periods of darkness (long night time). Usually less than 12 hours are required for these plants.
   • Long Day Plants – Long day plants are those that flower when exposed to short periods of darkness (short night time). Usually more than 12 hours are required.
   • Day Neutral plants – These types of plants are more likely to be influenced by age or stress, than different light lengths.
      
5. Growing Degree Days – Also commonly seen as “GDD”, this is the measurement of accumulated heat exposed to a plant, insect or animal over time. This allows the measurement to be compared to known phenological conditions in order to compare rates of growth and development.

What horticulture terms have you googled? Let us know in the comments below!