Using cell packs to germinate!

I only plan on growing about 100 seedlings next spring. I have built a four bulb, 6500 k, daylight type, light box. I have about 24" clearance to move the growing table up and down. The light box has reflective material on three sides. A small electric heater will heat the space below the growing table if needed. I am growing in a shop which will have heat maintained between 75 and 80 degrees. I have a timer on the lights and plan to use 16 hours on and 8 hours off to grow.

I've never been a fan of up potting seedlings. I prefer to plant and let grow. I plan on ordering a supply of 6 cell growing packs with holes in the bottom for bottom watering after the seeds germinate. The growing cells in each pack are 3 1/2" deep and about 2" X 2.25" long and wide. the cell packs will fit in a standard 1020 flat with 36 cells per flat.

I've noticed over the years that the commercial greenhouses who supply the nursery grown tomato seedlings to stores often use the same cell packs. When you remove one of the seedlings from the cell, it is usually root bound and about 12" tall with a strong main stem. I assume they plant the seed directly into the cell and allow the seedling to grow without up potting.

I plan on using a soil less growing medium filling each cell about 3/4 full. I will plant two seeds in each cell with the intent of removing the weaker of the two plants if both seeds germinate in each cell. I will cover each flat of cells with Saran wrap after planting the seed and moistening. I will remove the Saran wrap after the seeds germinate. I will use a small oscillating fan to move air around the seedlings after germination.

I plan on growing under the lights for four to six weeks moving the table down to accommodate growth. I will start germination with the cells about two inches below the lights. After four to six weeks, I will start moving the seedlings outside a little each day to harden off. At eight weeks of growth, I should be past my last frost date and ready to plant in the soil.

I have a pressurized spray bottle to keep the planting soil moist after I remove the Saran Wrap. I am curious if anything can be added to the spray mist to help prevent damping off. At some point I will probably add small amounts of fertilizer to apply in a foliar spray manner.

I've never done this, so feel free to shoot my plan full of holes. Every criticism you provide will help me improve my plans.

Thanks

Ted

[TZ-OH6]

I've never found a need for plastic wrap or misting. I fully hydrate (bottom water soak) the potting mix and find little water loss between sowing and the time the sprouts are several days old.


The problem with large seedlings in small cell packs is the frequent need to water and the possibility of sudden death if you don't get to them on time.

TZ,

I don't like watching my seedlings to determine if they need water. I plan on using a pair of scissors and remove one cell from the corner of one six pack to add water to the tray and view the water level in the tray. I will use a measured cup to add water each day. When I know how much water is needed each day, I will simply add the measured amount. All of that will be after the seedlings have germinated.

I've left six packs of nursery grown seedlings outdoors on some pretty warm spring days for a couple of days. I would notice the seedlings looking a little wilted, add water, and they usually would spring back up. If I monitor my seedlings daily, I think I can insure they get the needed moisture.

I think my biggest concern is getting enough light to each seedling when they start adding foliage. I don't know how the nurseries do it, but I am sure they have a professional lighting system compared to my home made system. Even growing close to the bulbs, I'm not sure enough light will penetrate the thick foliage in the cells.

Ted

[TZ-OH6]

You'll probably be putting them outside during the day before the foliage becomes too dense for the lights but even with full sun they will get leggy at that density. That is OK because with a tight rootball you will be better off deep/trench planting so adventitious roots can develop off of the stem.

TZ,

That is a good thought. I have always purchased the most "leggy" looking seedlings I could find because I do plant deep. I always feel shortchanged if I have to buy normal looking seedlings.

Ted

[ddsack]

I've noticed over the years that the commercial greenhouses who supply the nursery grown tomato seedlings to stores often use the same cell packs. When you remove one of the seedlings from the cell, it is usually root bound and about 12" tall with a strong main stem. I assume they plant the seed directly into the cell and allow the seedling to grow without up potting.

I have watched progress at some of our locally operated nurseries who start their own tomatoes, and I don't see any of them directly planting seeds into the four cell packs. Very often in early spring I will see workers separating and potting up mass starts of seedlings into the cell packs. Since % of germination is often a question, it would not be very cost effective to have empty cells where nothing came up, which could happen even with 2 or 3 seeds planted per square. The other benefit to transplanting is you can bury the stem up to the leaves, allowing for a stronger root system, and a sturdier stem which will tend to be stringy and weak if not given enough light.

[carolyn137]

I've noticed over the years that the commercial greenhouses who supply the nursery grown tomato seedlings to stores often use the same cell packs. When you remove one of the seedlings from the cell, it is usually root bound and about 12" tall with a strong main stem. I assume they plant the seed directly into the cell and allow the seedling to grow without up potting.

*****

I agree with Dee in terms of how commercial folks raise their seedlings.

For many years I did all my inside tomato work at a commercial farmers farm where Charlie had 28 greenhouses and a HUGE operation going on and he raised all sorts of stuff to sell wholesale to nursery outlets as well as his own plants for his own farm.

Cell inserts were never reused, all brand new, and here's how he and other commercial farmers that I knew raised their seedlings.

All I can say is that there's shaking machine that distributes the tomato seed to flats. When the seedlings are from 1-2 inches tall they are transplanted to cells at that time.

If seedlings aren't transplanted they form a tap root structure instead of the desired fibrous root structure, which Dee spoke to, so I don't know anyone who seeds cells directly and grows on tomato seedlings with no transplanting.

Charlie did direct seed some of the stuff he sold wholesale, but never tomatoes.

[Worth1]

A mixture of 1 part hydrogen peroxide and 10 parts water will prevent damping off. ( I just eyeball it)

When do you plane on starting seeds?

I start and grow seedlings in a room that is cool (about 60 degrees) and I dont use a heater.
If the room is already as warm as you say it will be then the heater will make the seedlings too hot (maybe)

If you start seedlings around the last days of December you should be able to put the seedlings out when the weather permits.
To me this means any days that are sunny and above 50 or so degrees.

My plants will stay outside as long as the temps dont get to freezing.
With this method I dont harden off the plants because the sun is still weak that early in the year.
Another thing is to protect the critters from high wind and when you first put them out the shade will do fine for a day or two then out in the fuul sun.

I disagree with starting in a cell as big as you are going to use for the same reasons as others have already spoken of.
I prefer to start in smaller cells and pot up one more time.
The reason being, I have more room under the lights, when they sprout and get about 2 sets of true leaves on them I will them pot up into a larger container. and out they go.
My plants are hardly ever leggy and I dont dig trenches or deep holes because I am too lazy.


I water seedlings with a mild solution of miracle grow.

Worth

Since I don't plan on starting the garden plants until mid January for Planting in mid March, I will experiment a little. I have some old six cell packs from past nursery plant purchases. I also have some generic "Beef Steak" tomato seed I purchased at one of the "Dollar Stores", five packs for one dollar. The packs have no information on them stating the variety or type. I will plant one of the six packs with the generic seed direct. I will start some more seed in a tray and then up pot into a cell pack after each seedling attains some true leaves. After about eight weeks, I can compare the two methods and see if one has an advantage over the other.

Worth, I used a very small amount of Miracle Grow added to the water for bottom feeding last year and it worked great. I didn't add it to a few potted plants, but did to others. The plants that received it about two weeks before plant out, were much healthier and larger with more developed root systems than the plants that didn't receive it. I only used about 1/8th teaspoon mixed in a quart of water for their last two weeks of growth. I wonder what it would do to young tender leaves as a foliar spray.

Ted

[carolyn137]

Ted, I doubt that you'll see any differences with seeds sown directly in 6-paks vs those you transplant b'c it has to do with the root structures and the differences would only be seen after the seedlings were planted inground or in containers.

And that's b/c fibrous root structures ( transplant) are superior to tap root structures ( no transplanting), for tomatoes, in terms of up take of water and nutrients.

Carolyn,

Thank you! I agree about the root structure difference. My intent is to examine the root structure of the plants grown direct in the cells and plants transplanted from a tray to cells. I will examine them after about eight weeks of growth.

I decided to not plant the generic beef steak seed and planted "Gary Ibsens Gold" instead. He sent me a pack as a bonus for a seed order I placed last fall. Not knowing exactly what they are, I had no intention of planting them in my garden. I planted six seed direct in a six cell pack and probably twenty seed in a tray. When the tray planted seed develop a few true leaves, I will transfer the strongest growing plants to another six cell pack and allow both six packs to grow for about eight weeks. I want to see how well the tap root plants fill the cells with fibrous roots compared to the disturbed tap root plants. I should be able to compare them just before Christmas. I did fill the cells on the six pack only about 1/2 full of seed starting soil. I've done that before and finished filling the cells with a teaspoon after the new seedling has grown true leaves above the tops of the cells. I've done that in the past when up potting to induce root growth from the buried stem.

Ted

[carolyn137]

http://www.soilandhealth.org/01aglib...010137toc.html

Most of the basic traits of tomatoes were worked out in the 20's and 30's, the pre-molecular era.

Above is a link to an article from 1927, just scroll down to the section on tomatoes that describes the differences between tomato tap root and fibrous structures.

[ddsack]

I have to admit, I do use the 4 cell packs to start seeds, but only to recycle and save myself some indoor space under lights. I start 3 to 6 seeds in each cell (depending on how many plants I will want.) I try to space them equidistant from each other using all four corners. I leave them there until the first true leaves are nice sized - or even start of 2nd true leaves, if I get behind. My seeds often have a 5 day gap between the first and last sprouts, and I will remove the faster growing seedlings with a butter knife to new quarters so they won't crowd out the slow sprouters. Eventually, only one seedling is left in the original square, but it's roots have also been disturbed and repacked, and new soil added each time the other seedlings were removed. This is more labor intensive than people growing large numbers for market would ever do, but it lets me separate out at an early stage seedlings that are ready to go out into a cool greenhouse from those unsprouted seeds and younger sprouts that can benefit from warmer temps under lights in my basement. I do try to get all seedlings out into natural light just as soon as I can, even if I have to carry trays inside at night.

Carolyn,

I had read the information/report before. I think the following sentence from the study pretty well makes the point."Transplanting or potting of seedlings tends to modify the natural taproot system into a more or less fibrous one, due to the injury to the taproot. The change in the root system is really very profound."

I believe they were comparing root systems of plants grown in containers and then planted in the soil disturbing the tap root versus root systems of plants grown directly in the soil.

It is my intent to grow the seed in trays and transplant to cells, versus seed/plants grown direct in cells. I want to compare the roots of both before both can be transplanted to the soil. (they will not be planted out because it will be the middle of winter)

I believe the eventual transplantation from the cells to the soil would result in the same fibrous root structure revealed in the study. I simply want to see if two transfers have benefits over one transfer. If I was planting the seed for spring plant out, both cell packs would eventually be transferred to the soil. I may repeat the effort and finish by planting the plants out in the spring.

I am still intrigued by the Juliet/non Juliet volunteer plants I allowed to grow with no supplemental water or nutrients versus the transplanted Juliets F1 grown in prepared soil with supplemental water and nutrients. I'm curious if the tap roots alone can account for the vigor of the volunteer plants through high heat, drought, and nutrient deficiency.

Ted

[RinTinTin]

If you read past the opening paragraphs, you will see that the conclusion is that transplanting actually harms the plants and production:

Quote
Since the root system is disturbed and the development of the plant more or less checked at each transplanting,
it might be concluded that plants grown from seed sown directly in pots or other containers would grow more
vigorously and give a higher yield than those once or twice transplanted.
In fact this has been shown by numerous investigations to be the case.
That transplanting in itself does not promote an early crop nor an increased yield has been also clearly demonstrated.

In an experiment in Wisconsin three crops of tomatoes were grown . . .

In each case seeds were planted singly in 6-inch pots in the greenhouse;
when the plants were about 2 inches in height, two-thirds of the whole number were dug up and reset in the same pots;
later, one-half of these were again transplanted in a similar manner.
As soon as weather permitted, 10 plants of each lot were knocked from the pots and set 4 by 8 feet apart in open ground,
every precaution being taken to avoid injury to the roots.

Those not transplanted yielded more than those once transplanted, while those twice transplanted yielded least.
The total for 10 plants with each treatment during a 3-year period was, 1,175, 1,131, and 1,001 pounds, respectively.
End of quote