To compare the germination rate of tomato seeds and the vigour of the growth of tomato plants, after seed exposure to the following environmental conditions:
If you are NOT registered, the first step is to register your class and follow the registration process carefully. The address you provide (including postal code) will become the label for your package. If it is incorrect, your seeds may not be deliverable. Ensure that your e-mail address is correct; electronic mail is used to provide you with occasional updates and is used to confirm your registration at www.tomatosphere.org.
Tomato seeds are relatively small, about 2-3 mm in length. They are light enough to be blown away in drafts from open doors and windows.
Seeds should probably be kept in their sealed envelopes until just prior to planting.
In this investigation you will be working with seeds from two different sources.
It is very important that you do not get them mixed up.
All seeds should be germinated simultaneously under identical conditions in order to control as many variables as possible.
Decide how and where you will germinate the tomato seeds. Peat pellets are strongly recommended.
Peat pellets can generally be purchased in one of two forms - in packages or in trays. In both cases the peat pellets are dehydrated and compressed. They will expand significantly when they absorb water, as shown in the photograph. Compare the fully expanded pellet on the left with its original compressed form on the right.
The packaged kind can be set out in the bottom of an empty margarine container or in a shallow pie plate. Covering the container with clear plastic wrap reduces evaporation.
If you make your own tray, its sides should be high enough to allow for the height of the pellets when they are fully expanded.
The peat pellets purchased in their own trays also come with their own miniature greenhouse "roof". Simply add water, plant the seeds, and cover them with the transparent plastic roof.
Space: You will be evaluating and measuring the germination properties of approximately 60 seeds, (Two sets of 30, each set having a different environmental history). This number of peat pellets will require a fair amount of counter space. Try to find a location to ensure, as much as possible, that all seeds are germinated under identical conditions. You will need labelled containers for 60 peat pellets.
HINT: 12-15 labelled margarine containers having 4-5 peat pellets each works well if you are using individual pellets. If you are using trays they typically contain 10 pellets each, so 3 trays for each group would work fine as well.
Time: Plan to have four (4), more or less, uninterrupted weeks in which to perform this experiment so that (except for weekends) observations can be taken, and recorded daily. It is also best to set up a schedule to identify students and times to make observations. Your colleagues have informed The Tomatosphere Project that it is best to plant on a Wednesday or Thursday in order to see the first germination the following week.
Procedure: Due to the important nature of this experiment it is essential that you develop a plan to keep track of which seeds are which. Develop a method to accurately identify each group of seeds.
Label all containers clearly and indelibly prior to planting.
Multiple forms of labelling can be helpful. For example, in addition to labelling the containers, gluing a container to a sheet of coloured paper, a specific colour assigned to each of the two groups of seeds is helpful. You might assign red to group A and blue to group B. In this way seed groups can be quickly identified.
Set up the germination centre before you actually plant any seeds. Is there enough space? Are the conditions of temperature, light, and humidity likely to remain uniform for all of the seeds during the experiment?
Decide where you will place the germinating seeds so they will not be disturbed and where uniform germinating conditions will exist.
Germinating seeds do not require sunlight. They do however require moisture, a moderate temperature (not too warm), and oxygen.
Do not place your seeds in direct sunlight (they may become overheated). A broad window sill where the temperature is about 20°C throughout the day is ideal.
If there is any chance that your seed trays will be exposed to direct sunlight, a provision to give them full shade should be implemented.
Caution: Some schools turn down the heat at night as an energy conservation measure. Under these conditions it can become very cold near windows unless curtains are provided. An alternative is to set up some form of barrier between the window and the seeds; this can be set up each afternoon before leaving. Heavy duty cardboard works well.
The first step is to soak the peat pellets for about 20 minutes in water at room temperature (or until they are fully saturated with water).
HINT: It is important to plant all seeds on the same day. However, to minimize the chances of accidentally mixing up seed-groups, plant only one seed group at a time into their appropriately labelled containers, Plant only one seed per pellet. Plant only one seed per pellet.
Tomato seeds are very small. Each seed should be pressed gently into the depression in the centre of the peat pellet, to a depth of about 2-3 mm, approximately the length of the tomato seed itself.
Place the pellet in its labelled container. (Hint: label the containers in such a way that there is no opportunity for their labels to be removed, accidentally or otherwise!)
Detailed and carefully recorded observations are essential to completing a successful experiment.
Observations should be recorded daily. Print out and make copies of the Data Sheet which is provided (or design your own).
Monitor the germination conditions.