How to Germinate Tree Seeds

Issue #6

Summer 1996

(image: Tim Cantor)





if you live anywhere in the world where temperature doesn’t freeze at night more than a week or two per year. A magnificant Ash tree, that grows rapidly to over 100 feet in height, with a diameter of 50-60 feet. The beautiful vase like crown is similar to that of the mighty Elm, but unlike the Elm, the Evergreen Ash (Fraxinus Uhdei) is not excessively vulnerable to disease or blight, and the Evergreen Ash, like its name suggests, does not lose its leaves in winter.

This tree is one of the easiest trees in the world to grow from seeds, as you will see. You can acquire the seeds from most any tree seed supplier, the one we used was:

Carter Seed Company

475 Mar Vista Drive

Vista, CA 92083

phone 619-724-5931 fax 619-724-8832

These seeds are collected fresh each April, and can be germinated without being soaked or softened in moist sand in a cool dark place (the way you prepare Pine seeds, for example, for germination).

All you need in order to propagate Evergreen Ash seeds, which are about one inch long, perhaps 1/8 inch wide, and 1/16 inch thick (thicker at one end), is a humidor. These are sold in most garden sections of large hardware stores, such as “Home Depot,” or “Orchard Supply,” you get the idea.


A humidor is any container that is nearly airtight. Using a humidor allows your seeds to stay moist without setting up complicated climate control systems involving mist emitters activated by humidity sensors. For around US $5.00, a humidor the size of a standard planting flat can be purchased. They are typically two square feet in size, with an opaque bottom section where you can put about a 1.5 inch deep layer of planting mix, and a transparent top section which fits snugly on the top rim of the lower half.


Before describing a custom humidor (and the advantages thereof), here is the way to germinate fresh evergreen ash seeds. Note that this method will work with many freshly gathered tree seeds. Mix up a planting media comprised of 50% peat moss and 50% sand. Some people use 33% peat moss, 33% sand, and 33% potting soil. Others use 25% peat moss, 25% sand, 25% potting soil, and 25% vermiculite. I’ve tried them all, and they all work. The professionals stick to the 50% peat moss, 50% sand mixture. It helps if you screen through a 1/4″ sifting box all the big chunks out of your peat moss and potting soil.

Once you have mixed your soil, get it moist but not soaking, then spread it into the bottom section of the humidor 1.25″ deep. The soil should be firm but not compacted. Sprinkle or place the Evergreen Ash seeds on the top of the soil about one per square inch. These seeds are extremely fertile and you should get nearly 100% germination. Once they are spread on the top of the soil, sprinkle a very thin layer of soil on the top of the seeds. This top layer of soil at the most should be .25″ deep.

Place your cover onto the humidor and gently spray more water onto the top of the mixture. Use a fog/mist nozzle that can be purchased at most hardware stores and screwed onto the end of a garden hose. Put the humidor in a cool and dark place, like under a shelf on the floor of your garage, or under a shrub in a cool spot in your yard. Put a plank under the humidor since otherwise the sides of the humidor will flex when you lift it and disturb the roots of the seedlings.

You should check your humidor once every few days. Within two weeks and possibly sooner you will have little sprouts of evergreen ash coming up all over. At this point get the humidor into an area where it will receive filtered light. You still don’t want it to get too hot, so keep it out of direct sun. Your challenge at this point is to separate each of these seedlings from the planting mix and transplant them into pots. But there is a better way – a custom humidor that uses individual planting tubes! Use the generic humidor described so far just to test the viability of your seeds, then start the main event in a custom humidor!



A humidor that has the standard two square foot rectangular top section, but which has 98 (7 rows of 14 per row) 8 cubic inch starter tubes comprising the bottom section.


- 1x store-bought plastic, two piece humidor

- 98x 8″ long, 8 cubic inch planting tubes (referred to as “cells”)

- 1x 2 sq foot rectangular 98 cell-holder tray

- 1x heavy duty aluminum foil, 15″ x 30″

- 1x piece of transparent 1/8″ thick plastic, 12″ x 24″

- 1x piece of 1″ x 1″ wood, at least 6 feet long

- a few dozen 5/8″ long wood screws

- 1x tube of silicon sealer

- 1x 1″ thick plank, 3 feet long, 1 foot wide

- 2x U shaped standard workbench cabinet handles


1) Cut the transparent plastic into four pieces. Cut two pieces into sides that are 4″ tall and 24″ long. Cut the other two pieces into ends that are 4″ tall and 12″ long. (These dimensions are not precise, make sure you measure the transparent top of your humidor, because these sides are to be assembled into a box that your humidor top sits on top of).

2) Assemble your four transparent pieces into a box by cutting 4 corner posts, each 3.5″ tall. Drill 1/8″ screw holes into the ends of the plastic with a variable speed drill on a slow setting. Attach the pieces to the posts one at a time and adjust the exact distance with a C clamp, using the humidor’s transparent top as a guide. Drill 1/16″ screw starter holes into the posts once the plastic is attached into place with the C clamps. Screw in the wood screws, making sure the corner posts are on the inside of each corner and that the 1/2″ of extra plastic is on the top of the box.

3) Take the bottom of the humidor and cut the top lip off of it. Use an exacto knife, and be sure to score the plastic a few times or you will not get a successful cut. When you are done you should have a 1 foot by 2 foot rim that will have a groove all the way around on its bottom. Squeeze silicon sealer into this groove, turn it over and place it onto the plastic box you have made. Also squeeze silicon sealer onto the corners inside the clear plastic box you made where the corner posts make contact with the plastic sides. The transparent top of the humidor can now be placed on and off the plastic box at will with a near airtight seal when it is on. NOTE: One modification would be to make the plastic box 6″ tall on each side, or more.

4) Use the rest of your 1×1″ wood to make a rim around the outside bottom of your plastic box. This box is going to be placed onto the top of the starter tube tray, so take care to make sure that your plastic box and the wood rim you make around the bottom is as perfectly level as possible. Screw the pieces of wood onto the plastic using the methods described in #2. The screw tops will be on the inside of the plastic box, of course, since the wood lip will run around the entire outside bottom perimeter.

5) You are now ready to prepare the starter tube tray. First of all, cut your plank to 1 foot by 3 feet in size, and attach the door handles on each side. The entire humidor, tray, tubes and all, will sit on top of this to prevent flexing either due to an uneven surface where the humidor is eventually deployed or due to occasional movement of the humidor.

6) Place the starter tube tray onto the plank. You may wish to put blocks on the plank to keep the tray legs stationary on the plank so that the whole thing doesn’t slide around when you move it. The next step is designed to complete the process of having an airtight humidor that uses starter tubes. Wrap a piece of heavy duty aluminum foil over the entire top of the starter tube tray, covering up the holes that the tubes are to go into. The tray has 7 rows of fourteen holes. Smooth the foil over these holes so you can clearly see each of them. Then poke a small X into the inner 5 rows of 12 holes (or fewer if you want to start with fewer seedlings). Your humidor will hold up to 60 tree seedlings!

7) Place the plastic top on the top of the starter tube tray, once the aluminum foil is in place. As you can see, with the top on, the tray is virtually airtight. Prepare your seedling mix as described earlier in this article. Moisturize the mixture and fill the tubes with soil to within 1 inch of the rim. Plant the seeds under about 1/8″ (not more!) of good seedling mix. Only after a starter tube has the seedling mix in place, the seed planted and moisturized, is the tube ready to insert in the tray. Gently poke the starter tube through an X in the tray. The hole in the aluminum will tear itself wider only enough to fit the contours of the starter tube, preserving an airtight humidor. Do the same for as many starter tubes as you have decided to germinate trees with. You can do up to 60.

8) Follow up: Put the humidor in a cool dark place for up to two weeks. It may be up to four weeks with some seeds, and some seeds need preliminary stratification, but more on that some other time. After the seeds germinate, put them in a cool area that gets heavily filtered light. Once the seedlings reach the top of the humidor, be sure to take the top off. Remember that once the top comes off you will need to water much more frequently. Prior to the top coming off the humidor you may not need to water at all, but check at least once per week. When the seedlings get between six inches and a foot tall, replant them in pots and watch them grow…

NOTE: You can get the starter trays and tubes from Stuewe & Sons who even have a web site at Ask for the “RL98 Tray with Super Cells.” Tell them Ed “Redwood” Ring sent you! And if the Stuewe site ever goes dark, drop me an email and I’ll email you their address and phone number.


Here is something for you eighth graders…and eighth graders at heart:

1) Determine square miles of planetwide tree canopy BC 8000.

The earth has 197 million square miles of total surface, 58 million miles of land surface. Originally 34% of the earth had tree canopy, meaning that the size of the original ancient forests was 20 million square miles.

2) Determine square miles of planetwide tree canopy at the present time.

These days forests cover 26% of the land surface of earth, making them 15 million square miles. This forest is comprised of 7 million square miles of original ancient forest, and 8 million miles of second growth forest.

3) Determine average number of canopy trees per square mile of mature forest:

If the trees are planted an average of 35 feet apart then the average crown diameter would need to be 40 feet to create a good canopy. This is a reasonable crown diameter for a big tree, which is the lynchpin of the polycultural forest – the new seringal. At 35 feet apart there are 25 trees per acre or just about 16,000 per square mile.

4) Calculate quantity of big canopy trees of world forests BC 8000.

It would take 320 billion trees to cover 20 million square miles with 16,000 trees per square mile.

5) Calculate quantity of big canopy trees today.

If there truly is 15 million miles of forest today, then there are 240 billion large canopy trees in the world.

You now know that 240 billion extra trees must be planted before the timber mass of the planet can double and the forests of the planet can recover to their original healthy glory!

The next step is to plan recovery, using the custom humidors described above. Each humidor can produce 50 trees per year, and occupies 3 square feet of space. This humidor is totally self contained, and therefore has an inefficient usage of space. None-the less, at this density the following calculation can be made:

Here at we believe that we will need to plant ten billion extra canopy trees per year for at least the next twenty five years – that’s right, 250 billion trees – if the goal of doubling the planet’s timber mass by 2045 is to be realized.

If each humidor produces 50 canopy trees per year, then to plant ten billion trees per year we would need to have 200 million of them in the world. If you laid them end to end and side to side they would consume 21.5 square miles. Area equivalent to a square 4.6 miles on each side.

The implications are staggering. A few small villages on each continent specializing in the production of these trees would result in reforestation becoming a real industry. Reforestation above the 10 billion tree per year increase would increase sustainable logging yields, serving growing world markets for timber.


If every EcoWorld gardener had one 20×20 foot greenhouse holding the equivalent of 80 humidors in 4 rows of 20 (they would probably be more efficient than that) they would produce 4,000 trees per year.

That means to achieve our goal of doubling the timber mass of planet earth we would need to have 10 billion trees per year being produced by no less than 2.5 million people.

That is only one backyard greenhouse for every 8 square miles of original 20 million square miles of planetary forests!

That’s only one backyard greenhouse for every 2,500 people! Piece of cake.

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Categorized | Other, Trees & Forestry
2 Responses to “How to Germinate Tree Seeds”
  1. Harold McEvers says:

    I am trying to find out how to harvest and then plant Evergreen tree seeds. We have millions of pine cones, but never seem to be able to get them to grow. Thinking we must be doing something wrong. Any help would be greatly appreciated.

  2. kamore says:

    we don’t have ash in Kenya.Can you send me a couple of seeds about 5 through mail. So concelled as not to be detected by Kenya Custom Authorities? If they have 100% germinability they 3 or 2 viable seeds would be enough.I get seeds from local trees and sell the same to raod side nursery men in Nairobi.So out of 100 trees planted around Nairobi.5 seeds that germinated from the tree possibly come from me .
    Please tell me if you can do me the favour
    kamore Macharia.(Nairobi. Kenya.)(MObile TEl:+254720651305)


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