Used Soil & peat blocking machines

About second-hand Soil & peat blocking machines

Soil blocking machine are used for making moulded plant plugs. These small pressed clumps of soil are used for raising flower or vegetable seeds such as lettuces and endives. A soil blocking machine does not actually make little pots, but small lumps of earth pressed together into a plug. By pressing the soil together, the plug remains intact and makes it easy to handle.

How the soil block pressing machine works

The soil block press squeezes together moist compost into small cubes of the desired size by means of moulding blocks. It is important for the pressing operation that the soil mixture is properly moistened. The soil mixture consists of a mixture of mainly black and white peat. In order to obtain the correct mixture, a compost mixer and/or a soil moisturiser is often used in combination with a soil blocking press. By changing the blocks various sizes of compost clumps can be made. The compacted soil clumps are drilled to make a hole for seeding and to make repotting easy. Depending on the type of soil block press, the plugs are automatically deposited by a dispensing rake from the machine into the ground or onto trays.With each different stamp comes a different size soil block, which in turn is used in different crops, below you can see an overview, which size soil block is available for which crop:

• 3.8 x 3.8 cm or 4 x 4 cm soil blocks; commonly used for lettuce, endive and various brassicas
• 4.5 x 4.5 cm or 5 x 5 cm soil blocks; usually used for beans, mangetout and tomatoes
• Larger soil blocks, for example 10 x 10 cm; are usually used for aubergines, peppers, pumpkins, courgettes, cucumbers and also tomatoes.

Soil mixture with black peat 

To create good soil blocks, it is important to use a fine soil mixture with 50-55% black peat and 35-45% white peat. The black peat is the "binder" of the mix. Black peat is more decomposed than white peat, has a finer structure, and much higher binding capacity. That's what keeps a pressed pot or block holding its shape without falling apart. It also retains moisture well, which matters because pressed pots have relatively little volume and can dry out quickly. Sometimes also other materials are added such as perlite, vermiculite or coco coir, lime or fertilization. 

Soil mixer to add water to create moisture

For pressed blocks you typically need a moisture level of around 60-70% (by weight). That sounds high, but it's needed because the peat has to be able to hold the water as a kind of "glue" between particles during pressing. A mix that's too dry simply falls apart after pressing; a mix that's too wet sticks to the press and produces soft, unstable blocks that collapse. 

How to test if it's right

The classic squeeze test: take a handful of the mix and squeeze it firmly.

• Does it form a ball without water dripping out, and does it break apart into pieces again under light pressure? Then you're generally in the right range.
• Does water drip out when you squeeze? Too wet.
• Does the ball fall apart immediately with no cohesion at all? Too dry.

It is possible to equip the soil block pressing machine with different types of seeders, such as a drum seederseeders, tilting and sliding seeders. Which machine is suitable for you depends on the type of seed. For example the tilting and the sliding seeders are used for spherical seeds like cabbage seeds and pelleted seeds. Drum seeders can sow virtually all types of vegetable and sunflower seeds.

The used soil blocking machines from Visser, Demtec (Dewa) and Flier which Duijndam Machines have currently on offer are all listed in the summary below. Our experienced and expert staff will be very pleased to help and advise you to find the most suitable previously used soil peat block pressing machines for you.