Place seed trays or containers on the flat. Fill to the rim with the compost and strike off level with a ruler or piece of wood. Firm very lightly. Water well and drain for at least half-an-hour before seed sowing. Always sow thinly, evenly, and not too deep. (A rough guide is 2 – 2½ times the diameter of the seed). Cover lightly with free-flowing moist Vermiculite; avoid over-firming. Place the containers in a propagator or in warmth (15°C-21°C) until seeds germinate then move the trays to a light position. Keep moist by a fine drenching mist as necessary. Seedlings are easily moved from a vermiculite compost without damage to the fine roots and they plant with a minimum of disturbance.
Use a hollow-tine lawn aerating fork in early autumn to spike the lawns, remove the cores of soil and brush-in Vermiculite mixed with autumn lawn food – about a handful thoroughly mixed to each large bucketful of Vermiculite and evenly distributed over a m². Before sowing new lawns, or repairing bare patches, lightly fork in one or two litres of Vermiculite into the top 10 cm per m². More even sowing can be achieved by mixing the seed with equal amounts of Vermiculite.
Softwood (geraniums, dahlias, chrysanthemums etc.)Make up a 50:50 mixture of Peat and Vermiculite. Fill the clean tray or pots to the rim; firm lightly. Set the cuttings almost touching but without overcrowding with the base of each cutting in firm contact with the compost. Water in and place the containers in warmth but shade from bright direct sunlight. Mist over each morning to maintain a humid atmosphere around the cuttings until they root.
Make 20 cm long cuttings using ripe current year's wood. Choose an open well drained site for a cuttings bed; make out a V-shaped trench about 20 cm and spread a mixture of 75% peat and 25% Vermiculite in the bottom half. Set the cuttings perpendicularly with their bases in the mixture: infill with friable garden soil and firm gently. Keep moist but avoid waterlogging by covering with a polythene tunnel or cloches during the wettest of the winter. Leave the cuttings for 12 months when most should be rooted and ready for transplanting.
Very light sandy soil can be improved by forking in Vermiculite to increase water-holding. Apply a 5-10 cm layer and fork into the top 15 cm. There is no organic content in Vermiculite and good dressings of farmyard manure remain necessary to increase fertility. Seed beds in heavier soils can be improved by working Vermiculite into the top 10-15 cm before sowing, using a hand cultivator or heavy rake and pushing and pulling to mix thoroughly. Mix Vermiculite with the garden soil used for infilling when planting roses or shrubs. It will help retain moisture and encourage new root growth.
The light weight of Vermiculite makes it ideal as a compost constituent for hanging baskets. Mix 50:50 peat and Vermiculite and water regularly with a liquid fertiliser incorporating trace elements.
The difference between 'seed' and 'potting' composts is mainly the fertiliser content. Little, if any, is needed for seed raising as long as very weak liquid feed is introduced with watering as the young plants develop; Vermiculite helps to carry the plant food in solution throughout the compost to be readily available to the searching young roots. Peat-based composts with added Vermiculite are much easier to wet than peat-only. Once they dry out. Potting composts have enough nutrients in their make-up to sustain early growth but as Plants develop and watering increases, nutrients can be washed out and regular top-up feeds need to be applied. By mixing proprietary composts formulated for 'seed', 'potting' or general use with Vermiculite, volume is increased in a cost effective way and the result is a lighter, open, free-draining compost that is easily wetted. Measure the required amounts of compost and Vermiculite mix. (Use dry Vermiculite for easy mixing) once mixed it will take up water readily and moisten the entire compost.
50% loamless seed compost and
or 100% Vermiculite
50% peat and
50% loamless potting compost and
Seedlings (annuals, tomatoes, pot plants etc.) and rooted cuttings (Fuchsias, Dahlias, Chrysanthemums, House plants etc.) grow quickly in a light mixture of 75% of potting compost and 25% of Vermiculite. Use moist free-flowing compost: place a little in the pot. Hold the plant centrally over the pot and trickle the compost round the roots filling almost to the top. Firm lightly and avoid excessive pressing down with fingers. A firm tap of the pot on a solid base is usually enough to settle the roots in the compost. Water in and set the pots in a light position in warmth. Pot-bound plants can be potted into larger size pots using a 75:25 mixture of soil-less potting compost and Vermiculite.
Dry Vermiculite is a good insulator and is ideal for winter storage of dahlia tubes, begonia and gladioli corms etc. Clean off all the soil and dry the tubers thoroughly in the open then place in large bags or boxes of Vermiculite making sure that the tubers/corms are surrounded by a layer of the Vermiculite. Keep in a dry frost-free place until early spring when they can be removed and boxed up for cuttings production (dahlias) or planting out.
Vermiculite is clean and sterile when made. Avoid contamination from dirty tools old soil in seed boxes and suspect plant material and you should have good results. Learn to grow clean healthy plants. Excessive compaction and over-watering can lead to disappointment but can easily be avoided. Let the compost dry out quite considerably before watering then water to wet the entire area: frequency of watering depends on the temperature, the size of the plants, the volume of compost in the pot or tray and the season.