Managing Peat-Free Media for Crops Under Cover
Greenhouse growing guide
Peat-free growing media are not a single recipe. A bag label tells you what the product is intended for, but ingredients and proportions affect how it holds water, leaves air around roots and supplies nutrients. Under cover, rain does not reach the crop, so media that works well in one container may need a different watering routine in another. Compare the finished mix with the crop and growing vessel, then check its behaviour on a small scale before filling every bed or pot.
Map the growing system before ordering media
Before comparing bags, decide where the media will sit: in an in-ground bed, raised bed, trough, pot, grow bag or propagation tray. Each format has a different fill volume and different access needs. Sketch the planted area rather than relying on the greenhouse outline; include paths, door access, room to handle bags and space to inspect plants. Record each vessel’s internal dimensions or labelled capacity. Plant count alone is a poor ordering measure because spacing and container size both affect the amount required. A layout also shows where crop groups need to remain separate.
Overall greenhouse area is useful as a scale reference, not as a measure of growing-media capacity. The T-Model Orangery Greenhouse listing gives area options from 16.52 m² to 30 m². Use the plan for the exact configuration to separate planted space from paths, benches and working areas, then measure the beds and containers you intend to fill. Mark where you will stand to inspect the medium and where bags can be opened without obstructing the entrance. Include propagation and mixing space if these are part of your growing system. An order list organised by bed or container group is more useful than one total based on the greenhouse footprint: it lets you assign each mix to its intended use and check quantities separately. If the layout is not yet settled, keep those measurements provisional rather than ordering enough media to fill an assumed planted area. This avoids tying your choice of mix and quantity to a layout you may still change.
Choose a mix for the crop and vessel
Look for the intended use on the label, not just the words “peat-free”. A product labelled for seed raising or propagation is meant for that stage; a mix intended for pots or longer-term vegetable crops may have different structure or nutrient provision. Check whether the product is suitable for the crop, the type of container and how long plants will remain in it. A mix made for one use is not automatically suitable for beds or every crop under cover.
If you are growing seedlings alongside established crops, plan where each group will sit and how you will keep the mixes identified. Different crop stages may have different watering and feeding needs, so clearly defined areas make routine care easier. When considering the Pyramid Greenhouse, compare the plan for your chosen configuration with the trays and pots you actually use, rather than treating the listed footprint as a crop-capacity figure. Label each group with the mix name and intended use so that a bag opened for established plants is not confused with your seed-raising medium. Before buying, also decide whether seedlings will move into a different mix when potted on. This separates the amount needed for propagation from the amount needed for the next growing stage. If you want one product for both, check that both uses are covered by its label; convenience alone is not a reason to assume that the same blend suits every stage.
Understand what the ingredients can contribute
Peat-free mixes may use ingredients such as coir, composted bark, wood fibre, composted green material and mineral additions. Their effects depend on the finished blend. Coir can contribute water-holding capacity; bark and wood fibre can help create a coarser structure; composted materials can contribute fine particles and nutrients. Perlite or pumice may help maintain air spaces. None of those ingredients, on its own, tells you exactly how a ready-made mix will behave.
Proportions, particle size, maturity and any added fertiliser all matter. A small amount of one ingredient will not necessarily dominate the mix, and the same ingredient can be used differently across products. Organic components can also break down during use, changing the structure over time. Ask the supplier what the blend is intended for and what information is available about its composition. Avoid making a full growing-medium recipe from raw ingredients by guesswork; trial a small batch in the vessel and crop you plan to use.
Check air space, drainage and root-zone stability
Roots need both moisture and air. A mix that stays saturated can leave too little air around the roots, while one that drains very quickly may need closer monitoring. Fine particles can settle or compact, especially if a medium is handled roughly or repeatedly disturbed. Coarser ingredients may leave more open spaces, but that does not guarantee the whole blend will retain enough water. Judge the finished product, not a single ingredient or a general claim about drainage.
Test the mix in the actual vessel before filling a whole growing area. Fill one representative pot or trough, wet it as directed, let excess water drain and look for settling, uneven wetting or a surface that becomes hard to penetrate. Record how you filled it as well as what happened afterwards: a comparison is less useful if one container was firmly packed and another was loosely filled. Check the middle of the medium, not just its appearance from above, and note whether the settled level still suits your planting plan. When assessing the layout of a Bloomcabin Prestige Greenhouse, allow access to these test containers so you can inspect them without disturbing neighbouring crops. Keep the trial focused on the combination you intend to use. A satisfactory result in a small propagation pot does not, by itself, establish how the same mix will behave in a different vessel. Compare like with like before committing the whole area to one blend.
Wet new media evenly before planting
A dry mix can be difficult to wet evenly if water runs through a few channels while other parts remain dry. This varies by product, so follow its label, especially for compressed blocks or media that must be rehydrated. If the instructions allow, add water in stages and let it spread through the material rather than pouring it all in quickly. Break up dry clumps gently; pressing or kneading the mix hard can damage its structure.
For a small test, moisten a representative amount, wait for it to absorb water and check the middle as well as the surface. If the centre is still dry, add water gradually and check again. The aim is an evenly moist medium that drains excess water, not a saturated container sitting in water. Use the same approach when filling a set of pots or trays so plants start in similar conditions. If a product’s instructions are unclear, ask the supplier before preparing a large quantity.
Adjust watering as the medium dries
Under cover, rain does not reach the growing medium, but that does not mean every pot needs water at the same interval. Dry-down varies with the blend, vessel size, crop growth, temperature and ventilation. A warm spell or increased airflow can change how quickly a bed or pot dries. Check beneath the surface at root depth instead of judging by the top alone. For pots, lifting or weighing the same vessel at regular times can help you recognise how its weight changes as it dries.
Make checks in more than one place, particularly where crops or containers differ. A single pot may not represent a whole row. The Spacious Greenhouse listing gives area options from 47 m² to 70 m², making a clear plan for reaching and checking crop groups especially useful when comparing layouts at that scale. Choose representative checking points for each mix and container type, and keep them identifiable so your observations remain comparable. Note the condition below the surface before watering, then check whether moisture has reached the intended root zone afterwards. This helps distinguish a mix that has dried from one that was never wetted evenly. Where one group repeatedly differs from the others, record it separately rather than using the average condition of the greenhouse to set its watering routine. Keep notes brief enough to use regularly: the date, crop group and moisture observation are more useful than an elaborate record that is soon abandoned. Adjust watering from those observations, not from a calendar rule.
Check nutrient supply, pH and soluble salts
Some growing media contain starter fertiliser and some do not; the amount and expected duration can vary. Read the product label before adding feed, particularly when planting into a new mix. Compost-based ingredients may also contribute nutrients, but that is not a guarantee that every crop will receive what it needs throughout its growing period. Follow crop-appropriate directions and avoid doubling up on fertiliser simply because a mix is peat-free.
pH and electrical conductivity (EC) are different checks: pH relates to acidity, while EC indicates the concentration of soluble salts in a sample. If you test either, use a method suitable for growing media and interpret the result for the crop and product. Keep the method consistent when comparing readings, and record which mix and crop group each sample represents. A number without that context is difficult to use. Leaf symptoms alone do not identify a nutrient problem; watering or root conditions can also affect plant appearance. Keep observations of those conditions alongside your feeding notes rather than responding to every change in appearance with more fertiliser. If you are comparing Aluminium Greenhouses, use the chosen layout to identify where crops with different feeding needs could be kept in clearly marked groups. This is a planning consideration, not a claim about a model’s growing capacity. The practical aim is to make each group easy to identify, inspect and feed according to its own requirements.
Choose a supplier who can explain the mix
Useful product information includes the intended use, the ingredients, any nutrient charge and available pH or EC information. If proportions or particle grades are not stated, ask whether the supplier can explain them. Check the declared volume and whether the product has specific instructions for wetting, storage or feeding. Clear answers help you decide whether the mix is appropriate for your crop and make it easier to compare products on more than the headline ingredient list.
Consistency matters when you want to repeat a good result. Keep the product name, batch details and label information, then note whether a later purchase behaves differently in the same vessel. When comparing suppliers, distinguish information about a particular finished mix from a general description of one ingredient. If an answer is unclear, ask which product or batch it applies to; this makes the comparison more useful without assuming that every blend from the same supplier is identical. Consider delivery and handling as part of your order, too. Bags need to reach a clean place where you can store and use them without blocking growing access. For a Lean-to Greenhouse, examine the selected plan alongside the route from your unloading point to the intended storage and filling areas. Neither a model name nor its listed area establishes those arrangements. Decide where bags will go before they arrive, and keep their labels available until the media has been allocated to the relevant crop groups.
Calculate the quantity and store it cleanly
For a rectangular bed, multiply its internal length by width and by the depth you plan to fill to get a volume in cubic metres; multiply by 1,000 to convert that figure to litres. For pots or bags, add the labelled capacity of the vessels you intend to fill. Compare the result with the volume stated on the media packaging. If a product expands when rehydrated or settles after filling, follow its instructions rather than applying an assumed allowance.
Keep unused media protected from rain, contamination and pests, and follow the supplier’s storage directions. Retain the label and batch information so you can identify the product later. Separate unopened stock from any opened bags, and keep different mixes identifiable rather than relying on their appearance. Your order list can also serve as a stock record: note which bags have been used and what remains for later planting. The Limited Edition Aluminium Greenhouses with Storage listing identifies a model described with built-in storage, but that name does not establish its storage capacity or whether media bags will fit or remain protected as needed. Check the precise product information against the bags you intend to store. Allow for access to retrieve them as well as space to accommodate them, and keep the working route clear. If you cannot establish that the proposed storage space meets the supplier’s directions, leave it out of your media-storage plan rather than counting it as usable capacity.
Use crop results to refine the mix
Keep a simple record for each crop group: mix name and batch, vessel type, planting date, watering observations and any feeding. Note whether the medium wets evenly, settles, stays too wet or dries between checks. This makes it easier to separate a media issue from a change in crop, container or care. If something is not working, adjust one factor at a time on a small number of plants so you can tell whether the change helped.
After a crop finishes, inspect the remaining medium for changes in structure, drainage and root condition before deciding whether it is suitable for another use. Compare those observations with your notes from planting: this helps you describe what changed rather than relying on a general impression that the mix performed poorly. Do not reuse material where disease is suspected without getting appropriate advice. Keep the question of reuse separate from the choice of mix for the next crop; the next planting may involve a different vessel or growing period even if the previous crop went well. If you change from beds to pots, or rearrange crop groups, remeasure the new set-up before ordering. When considering Limited Edition Aluminium Greenhouses, use the plan for the chosen configuration to map those future arrangements. Carry forward the records that remain relevant, but do not assume that the old media quantity or watering routine will suit a changed layout. A useful trial should leave you with a clearer basis for the next planting.
Frequently asked questions
Does peat-free mean the mix contains no fertiliser?
No. Peat-free describes the absence of peat, not the nutrient content. A finished mix may include starter fertiliser or ingredients that contribute nutrients, or it may have little added feed. Check the label for its nutrient charge and intended feeding period before adding more.
Do peat-free mixes always dry out faster?
No. Water retention depends on the ingredients, their proportions, the container and the crop. Some mixes hold plenty of moisture; others drain or dry more quickly. Check the root zone in your own set-up rather than changing to a fixed watering schedule based on the peat-free label.
Can I use the same mix for seedlings and fruiting vegetables?
Only if the product is labelled for both uses and its properties suit each stage. Seed-raising mixes and media for crops that remain in containers for a long time can have different requirements. Check the intended use and test a small amount before filling all your trays or pots.
Can I water every day in a greenhouse?
There is no reliable daily rule for every crop and growing medium. Temperature, ventilation, plant size, container volume and the mix itself all affect how quickly the root zone dries. Check below the surface and compare the same pots or growing areas regularly; water when the medium and crop need it.
What should I ask a growing-media supplier?
Ask what crops and systems the mix is intended for, which ingredients it contains, and what information is available on pH, nutrient charge and electrical conductivity. Check the labelled volume, batch details and any instructions for wetting, feeding or storage. These details help you compare products and repeat a successful result.
Managing peat-free media is a matter of matching the finished mix to the crop, vessel and growing conditions. Read the label, keep track of each batch and check moisture at root level rather than relying on a fixed watering timetable. A small trial and clear records make it easier to repeat a mix that works, or to make a measured change when it does not.
