Basic Growing Guidelines
These guidelines have been compiled by David Prescott, the Head of the Science Faculty at St. John's-Ravenscourt, a private school in Winnipeg, Manitoba. They have been compiled based on years of working with growth chambers in the classroom and provide commentary that correlates with the basic science labs posted in the Experiment Exchange.
Wisconsin Fast Plant Growing Tips
Gen1000 Plant Growth Chamber
The chamber should be set to 24-hour full light, 21⁰ C and 60% Relative Humidity. The plants will be fine at elevated humidity, but you may get more and faster mold development.
Planting
Choice of growing media is important. The recommended starter mix is very hydrophobic. It’s better to soak it first in a container and mix thoroughly. It’s difficult to soak it in the quads.
Vermiculite is hydrophilic, it works well in a 50:50 mix with any type of soil.
Three fertilizer pellets per plant works, less does affect growth.
Mixable fertilizers can be used, they should be as close to 14-14-14 as possible. Mix for continuous feeding and put into the watering tray. Do not put directly into the quads. The plants burn easily.
Copper sulphate will keep the algae from taking over. It works best if added around days 7 – 10, otherwise, it inhibits plant growth. The pre-prepared pads work but the concentrations are not consistent. 10 mL of a 5% solution works well. If you have extra mats this is a good time to change to prevent the algae from taking over.
It’s really important that the medium is very moist at the start. Otherwise, it will quickly dry out and affect germination.
The quads should be placed as close to the light source as possible, move the lights/plants after germination. The plants should be kept close to the lights at all times.
Germination
Plants will start to germinate in 2-4 days. Check the soil for dryness for any that do not germinate.
To prevent the plants from growing into the lights, the lights must be moved (sometimes daily).
If the plants grow into the lights, the heat will destroy the pollen.
Fast plants do not self-pollinate via air/wind, however, if the flowers come in contact with each other pollen can transfer.
Flowering
The plants will be ready for pollination around day 10.
The anthers with pollen look very fuzzy. Anthers that have been damaged by heat from the lights will be shiny. These flowers can be cut off and new ones will grow.
Pollinating
It’s best to try and pollinate between pairs of plants. One plant can be used to pollinate many if the students are careful and new pollination sticks are used. Any one plant should only receive pollen from one source.
Numbered plastic stakes can be used to identify plants that have been crossed.
I have the students use arrows when recording pollination. ie: 4 →5 indicates pollen was transferred only from 4 to 5, 4 ↔ 5 indicates that pollen was transferred from 4 to 5 and from 5 to 4.
The pollination wands can be cleaned with de-natured ethanol. Leave them in the ethanol for 10 minutes and then give them a really good rinse under running water.
Harvesting
Successful pollination will quickly lead to the formation of seed pods which will grow in length and width. Often the developing seeds will form “bumps” in the pod.
Unsuccessful pollination will result in stigma elongation with no increase in width.
The seeds must dry out before being planted. It doesn’t matter how they are left to dry, ie: in pods or out of pods. They should be left for a minimum of 5 days in low humidity, longer in higher humidity.
Cleaning
Watering systems and quads can be cleaned with soap and water, with a good rinse.
After being used a few times the mats will need to be bleached as the algae will form almost immediately. An overnight soak in 10% bleach is usually enough. They will need to be soaked in clean water overnight. Change the water and repeat. If they still smell like bleach, rinse again.
