There is a lot of scheduling decisions made on pott diameter. What about pot height? When odering six inch pots they range in height from 4 1/4 to 6 inches. What height is best?

The pot height you decide to go with depends entirely or personal preference and the demands of your individual market. The proportion of plant to pot is important in the finished look of potted flowering crops. Many growers and consumers prefer the height of the pot to only be 1/3 of the entire finished height of the plant (height of the plant + height of the pot). That said if you choose the shorter pot height or azalea pots your total finished height should probably be less, to keep proportion.

Culturally speaking, poinsettias will be happy in either the shallow or deeper containers. It's all a matter of preference.......

If it is only personal preference then why is scheduling based on pot size. The deeper six inch pot has the equivelent volume of soil as a much larger pot perhaps as large as an 8 inch pot. Would the post trasnplant grow period bfore pinching for a six inch deep pot be the same as for an eight inch pot? What is the objective of the longer growth period for the larger pots? Does the root mass have to fill the area before we pinch? If so the deeper pot would need more time just as the larger wide pot.

Scheduling is based on pot size because poinsettias follow a distinct growth curve and amount of growth the plants will put on is basically predetermined. Of course, there are exceptions to this that would affect the growth of the plant such as environmental factors but for the most part the schedules we recommend are based on the knowledge that certain cultivars will grow a certain amount in a set amount of time. Larger pot sizes require longer production time for more vegetative growth and to allow the plants to achieve a larger finished height.

To answer your question about the root mass and timing of pinch - we de recommend that the roots reach the edge of the sides of the pot (not the bottom of the pot) before pinch. This is a good indicator that the plant is ready to put its energy towards shoot growth. If pinched before the roots are allowed to expand properly the plant might not be ready to put energy to shoot growth because root expansion is always a priority. Hope this makes sense……..

To add to this discussion, pot size is also linked to the expected finished plant size. For example, most 6-6.5" pots have a finished height specification of 14-16" total height. Likewise, an 8" pot or larger might have a finished plant height requirement of 24-28" with similar width. As indicated in the response to your question, each market has specifications needing to be factored in for scheduling the plant and pinch dates. Generally larger, fuller plants require earlier transplant and pinch dates in order to yield the neccessary vegetative growth after pinch and before flower induction to make a good quality finished plant. Likewise, not providing enough vegetative growth time makes it difficult to yield a good quality finished plant because the shoots have not been able to develop enough green leaves prior to bracts and cyathia. Regarding root development, the goal is to develope adequate root mass before pinching.

If you have not checked out the scheduling information on our website you may want to...this helps growers factor different pot sizes, different cultivars (and vigor of each) and provieds a good overview of how to get the right balance of root establishment time, growth time after pinch, etc. for quality finished crops. The link for this document is:
http://www.ecke.com/html/tibs/tib_crop_schedule.html

Thank you for your help. I have used the scheduling information in the past. The pot size/volume question was just one that came to mind as I was looking at the 6 inch pot options that my supplier had for me. Please correct me if I understand wrong, the depth is not important only the width even though the plant roots would continue to grow down expending energy?

The depth is not critical when you are making scheduling decisions. Deeper depth equals more soil volume. Where this is an important factor is how you manage moisture levels in the container but scheduling is based on diameter not depth.