A seedbed is the space or container where seeds germinate under controlled conditions until seedlings develop that are ready for transplanting. In some contexts, they are also called hatcheries. Your goal is protect the early stages of life of the plant, optimize resources and increase the probability of success of plantings, especially with very small seeds such as lettuce, onion or tomato, which in their first period of vegetation require well-adjusted temperature, humidity and light.
Working with seedbeds allows for a better use of land and a early selection of vigorous plants, what translates into more productivity and a more accessible agricultural activity for the whole family. In addition, they facilitate the garden planning by allowing crops to be advanced or staggered without depending entirely on the outside weather.
Types of seedbeds according to their construction and use
Depending on the available area and materials, we can distinguish several configurations, each with specific advantages:
- Portable seedbeds: They are moved as needed. Ideal for small crops and for taking advantage of warm or bright areas. They are built with wooden or plastic cratesEven polyethylene bags resistant, with drainage holes. As an extended reference, they usually hover around up to 4 m long x 1 m wide and 10 cm deep for manageable tables/drawers.
- Temporary or transient seedbeds: are used only once or for short duration. Frequent in specific sowing campaigns. The usual width is around 110 cm and an approximate height of 20 cm, with the length that the terrain allows.
- Semi-permanent seedbeds: neither temporary nor fixed, they allow for easy crop changes. they fence with boards and brick to improve stability; common measures: 110 cm wide, 20 cm tall and length depending on availability.
- Permanent or fixed seedbeds: designed for continuous use. The edges are made in cement or block and the background with pellets or gravel to enhance the sewer systemThey require initial planning, but offer durability and proof of results.
In addition to the structure, the cultivation format determines the technique and management:
- Alveolar trays: allow order and uniformity, facilitate irrigation and monitoring. They are very practical for cabbages, leeks, tomatoes, eggplants and flowerbed flowers. With very small seeds, mix them with fine sand helps to achieve a homogeneous distribution.
- Individual biodegradable pots: ideal for species that They tolerate transplantation poorly or that require more time in the seedbed. They are transplanted with their own root ball, minimizing stress. Perfect for cucumbers, gherkins, zucchini, melons, watermelons, tomatoes and eggplants.
- Indoor grow boxes: wooden, metal or brick structures with transparent lid (glass/plastic) that opens to ventilate and waterWithout a bottom, they are installed directly on the floor or house trays inside.
- Culture tunnels: arches and plastic covers that provide luminosity, protection from the wind and less direct humidity over the seedlings. They are ventilated by raising one side to avoid heat hits and excessive condensation.
- Individual plastic protectors: they act like mini-greenhouses for larger seedlings (e.g., corn), accelerating its establishment and protecting it from weak frosts.
- Nonwovens: light covers over the seedbed that accelerate germination, protect from insects and storms and cushion thermal variations.
Where, when and how to prepare the seedbeds?
The optimal location and timing depend on the thermal requirement of each species. Many warm-weather vegetables (e.g., tomato and eggplant) are grateful to start the cycle in a seedbed at the end of winter Instead of waiting for good weather, always with a lot of light y temperate environment. Plants of tropical origin require pay extra attention to the heat and thermal stability.
Indoors or under cover, look for spaces with stable temperature y good lighting (specific natural or artificial). In warmer climates, some species may sown directly into the ground if the soil temperature remains high, but the seedbed usually offers better guarantees in the critical germination phase.
For an early protected outdoor seedbed, boxes y tunnels They capture solar radiation, raise the internal temperature and can gain up to a couple of weeks in advance for more resistant species. If there is a risk of night frost, cover the boxes with rice straw helps cushion the cold.
Sowing in trays and pots: key techniques
When sowing in a tray, distribute the seeds homogeneously. With small seeds, mix them with fine sand to avoid excessive densities. Cover with a very thin layer of substrate (or vermiculite) and water gently until the entire mixture is moistened without flooding.
In biodegradable pots, an effective practice is to sow 3 or 4 large seeds (o 5 to 7 small seeds) per pot and, once emerged, preserve the most vigorous seedlingThese pots allow transplanting without breaking up the root ball, reducing transplant stress.
If you group several species in the same tray, combine families with similar rhythms or even flowers and vegetables, maintaining a clear irrigation and lighting plan. For tomatoes and flowerbeds, the alveolar trays squares They are very comfortable if you need many identical specimens.
After the first phase in the tray, it is advisable ring (transfer to individual pots) when the seedlings have 2-3 true leaves, strengthening their root system before planting them in the final soil.
Seedbeds outdoors already covered
With proper protection and early varieties, you can raise early seedlings of beet, carrot, celery, cabbage, lettuce, turnip, pine, pea, radish and tomato. The boxes with transparent cover allow a rapid ventilation and irrigation management, and they work well both when sown directly on a layer of substrate or when trays are placed inside.
The tunnels provide great luminosity and shelter against wind and excessive humidity. They are not an absolute shield against intense cold, but they are an effective barrier against air currents y condensations. It is important ventilate by lifting one side, especially during sunny winter days, to avoid rot y thermal stress.
The individual plastic protectors They are useful for seedlings with a growing habit such as corn, acting as small greenhouses. During the first few weeks, they improve the local temperature and protect from ice.
La nonwoven fabric installed on the seedbed accelerates the germination, reduces the impact of flying pests and protects from heavy rainsRemove or lift the cover during warmer hours to allow air to circulate.
Step by step: from seed to ready seedling
1) Container Preparation: Use trays, biodegradable pots or recycled containers with drainage holes. clean and disinfects previously (water with a few drops of bleach or specific products, rinsing well) to reduce the risk of damping-off and other diseases.
2) Substrate and initial humidity: fill with one fine mix For seedbeds, moisten evenly and allow to drain. The texture should be light, airy and fertile.
3) Sowing and covering: Place the seeds according to the instructions for each variety. As a general rule, depth equal to 2-3 times the size of the seed (in many fine vegetables, slightly less than 0,5 cm is enough). Cover with a thin layer of substrate or vermiculite.
4) Gentle irrigation and microclimate: water with spray or with a fine-drop watering can to avoid digging up seeds. Place a transparent dome or film on the tray to keep heat and humidity stable, gradually removing it when germinating.
5) Light and temperature: place the seedbed in a location brightavoiding intense direct sun that the substrate dries out excessively. Control the temperature according to the crop, reinforcing with background heat in species that require it.
6) Chipping and hardening: When they form 2-3 true leaves, transplant them to individual pots if necessary. Before transplanting to the ground, harden off the seedlings by exposing them to gradually to outdoor conditions (more ventilation, small temperature drops) for several days.
Ideal substrate and recommended mixes
A good seedling substrate should be fine, porous and draining, able to retain moisture without compacting, and providing gentle nutrients for starting. Combinations with peat or coconut fiber, perlite for aeration, vermiculite for water retention and earthworm humus as an organic fertilizer.
For common cycle vegetables, a practical formulation is: 60% base (universal substrate or peat/coconut mix), 20% worm humus (fertility), 10% perlite (aeration) and 10% vermiculite (water retention). If you need more initial push, you can increase the humus up to ~40%, adjusting the percentage of the base accordingly to maintain a balanced structure.
To tubers and underground species a base of 75% black peat 25% perlite to promote aeration and prevent compaction around the thickened roots.
Remember that a specific substrate for seedbeds usually includes fine sand to improve the texture, and that the initial fertilization should be moderate so as not to damage young roots.
Containers: from commercial to recycled
You can use commercial trays and pots (peat, cork, plastic) or give second life to packaging everyday. The important thing is to guarantee sewer system y operating comfort: more information about protected seedbeds
- Diary paper: by making cones you get containers biodegradableReinforcing the base helps its stability.
- Cardboard rolls: Toilet paper rolls, with a formed base, are ideal and compostable.
- Supermarket trays (porexpan/plastic): useful if you incorporate holes at the base to drain.
- Eggshells: a creative and educational option. They can be planted as it is; they contribute Calcium to the soil as it degrades.
- Yogurt cups and containers: practical for the intermediate step when the seedlings are tight in the tray.
- Plastic bottles and bricks: when you cut them you get containers deep, very useful for species that need long roots (for example, germinate pinions for pines).
- Egg cartons: easy to handle and biodegradable; by cutting the base you will be able to plant the socket directly.
Whatever the container, fill it with seedling substrate, compact lightly, perform a small groove for seeds (usually 2 per point) and cover with substrate. The vermiculite optional on the surface helps to retain moisture already released nutrients gradually. The first waterings should be with spray until thoroughly soaked without displacing seeds.
Essential cultural work
In seedbeds, the cultural tasks begin at sowing and continue until transplanting. The most important are: irrigation’s most emblematic landmarks, the weed control’s most emblematic landmarks, the pest management and the disease Control:
- Irrigation: avoid excess. As a guide, mild conditions are sufficient. 2-3 waterings per week, adjusting to climate and substrate. It is preferable to water with fine spray so as not to dig up seeds.
- Luz: lots of diffuse lighting. Use shading tights if the radiation is intense and avoid the strong direct sun in very tender stages.
- Temperature: Maintain optimal ranges per crop. In greenhouses, the thermal screens or background heat helps to stabilize.
- Ventilation: essential in boxes, tunnels and with domes to reduce condensation and prevent mushrooms.
- Hygiene: Disinfect trays before each use. Remove diseased plants and weeds as soon as they appear.
- Labeled: notes species and sowing date to monitor development and the optimal time for transplantation.
Advantages and disadvantages of using seedbeds
Among the main and advantages include:
- Greater control of density, depth and germination conditions to select vigorous seedlings from the beginning.
- Less seed loss to protect from pests, diseases and environmental fluctuations.
- Temporary flexibility: You can advance or extend the season with the help of canopies and gentle heat.
- Substrate choice most suitable for each species, favoring a homogeneous start.
Consider as drawbacks following:
- Possible root damage when extracting for transplantation if they are not used biodegradable pots or careful techniques.
- Transplant stress: Gentle handling and proper tools reduce risk.
- In some species, the cycle may be lengthened compared to direct sowing (for example, tomato), offsetting with a best establishment.
What to sow in a seedbed and what to sow directly
They require or appreciate seedbed: cucumbers, watermelons, celery, artichokes, broccoli, tomatoes, onions and leeks. Also flowerbed flowers and species with small seed or significant thermal demands. They can be direct sown (depending on climate and soil): potatoes, carrots, beans, spinach and strawberriesIn warm climates, some of the latter can also be started in seedbeds to optimize space and protection, although not essential.
If you're looking for early seedbed outdoors, opt for varieties early and resistant, and protects with boxes, tunnels, protectors or non-woven fabrics to ensure regular germination and emergence.
For those who enjoy documentation and visual references, you will find abundant graphic material in multimedia collections dedicated to seedbeds in specialized libraries and repositories.
With basic planning, suitable containers (commercial or recycled), well-formulated substrates and good management of light, temperature, humidity and ventilation, seedbeds become an extremely useful tool profitable and reliable to start crops and flowers with a high probability of success, both indoors and outdoors.