Construction and Use of Frames and Lights in the Home Garden

New Zealand Journal of Agriculture, Volume 87, Issue 1, 15 July 1953, Page 65

Construction and Use of Frames and Lights in the Home Garden

FEW if any districts in New Zealand are frost-free and all growing areas are subject to a greater or less degree to cold wind and io temperatures that at times are too low for the satisfactory growth of many of the plants it is desired io grow in the vegetable garden. Many keen, home gardeners are interested in extending the growing period of some of their vegetable crops, growing out-of-season crops, -or growing crops not completely hardy in their districts. One way of doing this is by the use of garden frames, certain types of which can be made simply and fairly cheaply. heir construction and use are described by A. G. Kennedy, Horticultural Instructor, Department of Agriculture, Dunedin, in the first part of this article. The section on garden work for August is by S. O. Gillard, Horticultural Instructor, Department of Agriculture, Auckland. GARDEN frames need not be elaborate. The simplest type and one which if placed in a sunny, sheltered situation will give some protection from frost and good results in raising seedlings is made of 4 planks stood on their edges and nailed together to form an open, bottomless square or rectangular box. Stakes or narrow battens are laid across the top to support , a cover of scrim .or sacking, which is put in place at night when there is danger of excessively low temperature or killing frost. The planks forming the side should be from about 6 to about 15in. wide, the width being governed largely by the crop grown. Small plants, which are readily overshadowed, require only a low wall. Ideally the frame should face north and be higher at the back than at the

front to give a maximum of shelter without restricting light and to facilitate run-off of water from the covering material. The planks forming the sides should preferably be lin. thick, as thin timber warps more readily. As an alternative to wood the sides can be of other materials, such as bricks or turves cut to the shape and about the size of a brick. A wooden frame has the advantage, important in larger gardens, of being moved easily. Thus even if plants are not raised in boxes, shelter can be given to successive sowings.' / Simple Glass Cover As a cover, glass is preferable to scrim or sacking, as it admits light and can be left on growing plants dur-

ing the day. It is more effective than scrim or sacking in excluding draughts and in retaining heat, important considerations in plant raising. Simple glass-covered tops for frames can be assembled even by those without skill in carpentry if light T iron is used to support the sheets of glass, the edges of which are laid in the angles formed by the inverted T iron as shown in the lower diagram on page 68. Each sheet of glass is overlapped | to 3/16in. by the sheet'above- and held in place by its own weight.-. The glass is’ unlikely to shift unless an opening large enough to admit wind is left in the frame or between panes of glass. The back of the frame should be higher than the front to permit rain and, on the under side, condensed moisture in droplets to drain off. A disadvantage of this loose-glass type of frame compared with one with a movable sash is the difficulty in giving ventilation, which is necessary in raising seedlings when moisture 'condenses on the under side of the glass. Where the glass is laid on iron the frame should not slope too steeply or the glass will slide, but in frames lying to the sun the steeper the slope of the glass,-up to a very steep angle, the better will be the admission of light. In New Zealand frames are not usually built to very steep angles because the gain through the refraction of light rays at steep angles does not compensate for the added cost of building high-backed frames, and . most plants commonly grown in frames in New Zealand do not have exceptionally high light needs, and those (such as tomatoes) which do are not in the frame long enough for any lack of light to affect them adversely.

Late-autumn, winter, and earlyspring light conditions, too, are generally better in New Zealand than in many Northern Hemisphere countries where frames, often quite steep ones, are used extensively. In New Zealand an angle of about 10 to 15 degrees is usually ■ considered adequate. The importance of sloping the glass enough to facilitate drainage of moisture which has condensed on the under side of the glass to the extent of forming droplets is often overlooked. Condensed moisture in quantity greatly reduces the light rays passing through the glass and may draw up and weaken small plants such as seedlings. Light Needs of Plants Modern conceptions of plant needs differ from those of a few years ago in the stress laid on the admission of as much light to most growing plants as is consistent with reasonable economy in the construction and operation of structures used in propagation. One of the chief develop-

ments is the use of larger panes of glass in glasshouses and propagating frames. : Sash and glasshouse astragal or sash bars are more widely spaced, resulting in a saving of wood and putty and labour m construction. However, beyond a certain point, the cost of glass rises so that, in New Zealand, the use of the larger panes results in higher initial costs. Whether commercially the higher costs would be offset by subsequent increased returns due to the improved production would depend on the relative value of the crop grown and its light needs. An example of the use of large sheets of glass in a frame or glasshouse is the Dutch light, which is made of a single large sheet of glass (usually about 32in. by 58in.) in a light wooden frame of durable timber, which may be morticed like an ordinary window sash or nailed with galvanised or other non-corroding nails or screws. In Europe Dutch lights are commonly used commercially on

garden frames and in the construction of glasshouses. Apart from the initial cost of the large sheets of glass in Dutch lights an important reason for the continued popularity of the older types of sash is that they are less expensive to repair if glass is broken. In commercial practice the standard sash is about 6ft. by either 3 or 4ft., usually with three or four rows of panes respectively, though occasionally smaller sashes are used for convenience in handling. The middle photograph on page 67 is of a commonly used type. The lower edges of the bottom sheets of glass overlie the bottom rail so that water drains off. Each successive sheet of glass laid overlaps the sheet below by about | to 3/16in. Wide overlaps should be avoided as dirt accumulates in the overlaps and restricts light. The top edge of the final or top sheet is let into the top rail so that water falling on it or on the top rail runs down the line of panes, over the wooden rail at the bottom, and off. An ordinary window sash is useful as a garden frame and one is shown in the upper photograph on page 71. Its main disadvantage is that water on the glass does not shed and this dampness will cause rotting of the timber. For a garden sash the bottom rail should be set under the lowest sheet of glass, there should be no wooden cross-bar, and sheets should overlap so that each sheet from the top downward overlaps the one below it. Sashes can also be made so that the glass is slid into position in grooves which run up the insides of each of the long side stiles. If of durable timber and used at a fairly steep slope, such sashes do not need putty. Other types are glazed like glasshouses; that is, the putty, which should be soft and easily worked, is first run with a putty knife on each side along the projecting shelf of the sash bar, the glass is pressed firmly on the putty and fin. brass brads are driven into the wood, one on each side, about lin. above the bottom edge of the pane to hold it firmly, in position. It is prevented from slipping down by two other tacks, one on each side, previously driven

about I to 3/16in. from the top of the previously set pane to hold it firm at the top. The same system of puttying and nailing is carried out on the next pane, which again overlaps the top of its predecessor by about j to 3/16in. Excess putty is removed parallel to and on the same plane as the top surface of the glass. Contrary to earlier glasshouse practice, the angle in which the edge of the glass lies is not puttied. Soil Usually plants grown in frames are specially valued because they are grown out of season. It is important therefore that they should be given as favourable conditions as the physical limitations imposed by aspect and the construction of the frame will allow. One of the most effective ways of creating a favourable environment is by using soil suited to the crop grown. Though satisfactory results may be obtained by using ordinary soil, good results are more likely if the soil mixture is specially prepared. A satisfactory soil for most of the commoner plants is a mixture of 2 parts of clean, turfy loam, 1 part of clean, coarse sand, and 1 part of leaf-mould, rubbed through a or gin. -mesh sieve. To each bushel (an apple case is a convenient bushel measure) of this soil should be mixed in about 2oz. of superphosphate, 2oz. of blood and bone, and about foz. of sulphate or muriate of potash. If the soil has not recently been limed, about loz. of carbonate of lime also should be added. For a seed-bed for very fine seed the top j to 3/16in. of the mixture should be sieved with an jin. sieve. The soil in the seed boxes should be level or the seed-bed may be damaged by watering. Turfy loam and leaf-mould are not essential; ordinary garden soil and compost can be used, but as they frequently contain many disease organisms which attack seedlings, they should be sterilised before use. For convenience in handling, plants are best grown in fiat boxes placed in frames. The boxes should be of a size that can be handled conveniently and the most commonly used size is about 20in. long by 15in. wide by 2j to 3jin. deep. Good drainage is essential and special attention is necessary if the plants are grown in the soil of the frame. With boxes either the ’ soil is kept so shallow, that water drains readily out the holes or through the slats in the bottom, or a layer of loose, open material (such as rough leaf-mould which is too coarse to go through a coarse sieve) is placed over the drainage holes in the bottom before the soil is put in. For cuttings clean, coarse sand free from dust or clay or a mixture of soil and a high proportion of clean sand is usual. Usually the frame is shaded or partly shaded and kept sufficiently closed to keep humidity high and reduce moisture loss through transpiration. In this way many types of cuttings can be kept from wilting until they have developed roots. With all propagating operations cleanliness is very important, as many harmful diseases are favoured by high humidity and decaying organic matter. Seedling Diseases Even where precautions are taken before planting, seedlings may be attacked by various diseases, which

may be soil or water borne, carried over in seed boxes or spread by tools, or transmitted by insect pests. Recent experimental work has shown that one of these diseases, foot rot of tomatoes (Phytopthora cryptogea Pethybr. and Laff.), commonly causing serious loss in seedlings can be controlled by use of a proprietary brand of copper oxychloride at 1 or 2 per cent., and that the more,, commonly used fungicidal substances, formalin at. 0.25 per cent. (1:400) and Cheshunt compound at 1 per cent, also gave satisfactory control without injury to seedlings. It is likely therefore that any of the above materials at the strengths given would be 'effective in the control of most of the other minor fungous diseases which attack seedlings. Several other fungicidal substances tested by the research workers gave control but damaged the seedlings. Soil Sterilisation Most garden soils that have been cropped consistently for some years contain many disease organisms harmful to seedlings and for that reason it is advisable to disinfect or partly sterilise such soils when they are used for raising seedlings. This can be done with steam or chemicals. Small quantities can be steamed in a sack suspended over a little water in a wash boiler with the lid on, or in the open by using a drum such as a 5-gallon oil drum. The oil drum should have the top cut out and then be burnt out to remove the oil. Two half bricks or blocks of wood should then be put in the bottom and covered with water and the cut-out top dropped on them. The drum should then be filled above the dropped-in top with loose soil, and placed over a fire. When the soil at the top of the drum is much too hot for the hand, most harmful disease organisms should be destroyed, but to be on the safe side it is usually best to maintain the fire for a further 10 minutes before removing the soil. Alternatively the soil can be treated with formalin or chloropicrin.- Formalin is used at 1 gallon to 49 gallons of

water, and 50 gallons of the mixture should be sufficient to treat about 1| tons of soil. The soil, which should be free from lumps, should be spread in a layer 6in. deep, watered with the solution, and either, covered with wet sacks or with another layer of the soil to be treated. When the heap is high enough, usually 2 to 3ft., it should be sprayed with water, covered with wet sacking, and left for 2 to 4 weeks, after which it should be turned to dissipate the fumes. As formalin will damage plants, the fumes must be completely dissipated before the soil is used. Treated soil should be dug oyer a number of times (fine, loose soil, less frequently than heavier soils) until all trace of formalin smell has gone. This may take as long as 6 weeks. . Chloropicrin, a tear gas, can be used, but owing to the risk of irritation to the hands, eyes, or lungs or more serious effects, it is not recommended to home gardeners. Experience in handling, the use of a suitable gun for in-

jecting, and a good gas mask are essential for safe use. Methods of Heating Frames Well-built frames in favourable sites should, under proper management, retain sufficient heat overnight to ensure that night and day temperature variations are not great, but in frosty weather it is usually necessary to close frames in the afternoon before the direct sun heat is gone, and in the colder districts that is usually at least an hour before sundown. In addition where very heavy frosts are expected the glass should be covered with sacking or scrim. Animal Manures or Refuse Where there is insufficient sun heat for good growth it may be necessary to provide artificial heat. One of the simplest and cheapest ways is to put in the bottom of the frame a layer of material such as horse, fowl, pig, or other animal manure, spent hops, or rubbish which will create heat while decomposing, such as that used to make compost. Horse manure, provided it does not contain too much straw, is one of the best materials, as its behaviour is more predictable than that of most of the other substances. It should be moist without being wet and should be turned at least twice at intervals of about 3 or 4 days to ensure that bacterial action throughout is uniform. It can then be placed in the frame, where it should be firmed gently. If it is beaten down with the back of the fork used to turn it, consolidation should be adequate. If garden trash and similar mixed materials are used, the general principles governing the making of a compost heap should be followed. Soft, green, nitrogenous materials or animal manure without too much litter should be mixed or layered with wet, fibrous material. A sprinkling of lime should be added every few inches, as bacterial activity will be greatly reduced if conditions are too acid. Moisture is essential, but the heap should not become too wet, particularly if of material which readily becomes soggy. Excessive firming of material which tends to consolidate should be avoided and additional ventilation should be given by making holes with the handle of a. rake or similar tool about 10 to 15in. apart down into the heap. ■* . The depth of the layer of fermentable material placed in a frame

depends on its composition. Readily fermentable material such as horse manure or spent hops need be only about Gin. deep, though deeper beds usually retain heat longer. Garden trash should be at least 24in. deep and properly layered. A layer of soil should be put on top of the fermentable material. It need be only lin. deep if the plants are to be grown in boxes, but if plants are to be grown in the soil of the frame, it should be deep enough for root action and should not dry out or be overheated; 6in. is usually about the best depth. Fuel Heaters or Electricity As an alternative to heating by fermentation frames can be heated by oil- or kerosene-burning heaters or by low-tension electric cables. There are a number of heaters on the market which are capable of heating frames or small glasshouses. The number of cubic feet of air space a heater is capable of heating is usually given by the maker or if the output in British thermal units is known, the space it is capable of heating can be determined. The larger heaters should be fitted with a chimney or flue to allow fumes to escape, and care is necessary, particularly where there is no escape pipe or flue, to ensure that combustion is complete, as fumes, particularly those of partly volatised oils, can be very damaging to the foliage of plants such as tomatoes. Choice of a heating system should be governed by the lowest outside temperatures likely to be experienced, the inside temperatures needed, the loss of heat through a glazed structure (which is much greater than that of a structure of wood, brick, or similar material), and the heat output of the heating unit. For heating by low-tension electric cables a transformer is necessary for the reduction of the voltage from 230 to 12 and the heat is applied through a galvanised-iron wire circuit, which is usually placed from about 1 to 6in. deep in the soil. If plants are grown in boxes placed on the soil, lin. of soil may be sufficient, but if they are grown in the soil, they need a much deeper root range; 6in. has been found satisfactory for a great range of plants propagated in electrically heated beds,

though slightly shallower soil is satisfactory for some subjects if watering is done carefully and the heat is kept low. A soil thermostat should be installed through the side of the frame about lsin. above the level of the wire and the soil can thus be maintained at the desired temperature, which* is about 60 to 65 degrees F. for most propagating work. The area of the soil to be warmed will determine the capacity of the transformer required and the gauge and length of the wire circuit. When warming is thermostatically controlled about 6 watts to each square foot of soil is sufficient. The amount of power used by a small unit is small and owing to the low voltage used there is no danger to the operator, but because of restrictions on electricity, permission to install may not readily be granted by electrical authorities. For those interested, fuller details of electrical soil heating may be obtained from the Storage Specialist, Department of Agriculture, Wellington.

Preservative Treatment of Timber . Durable timber is rarely available for seed boxes or frames and to extend the life of the wood used in construction it is advisable to apply some form of preservative. Oil-soluble wood preservatives such as zinc naphthenate (2 per cent, metal by weight), copper naphthenate (1 per cent, metal by weight), and 5 per cent, pentachlorphenol are available as proprietary lines and, applied with simple brush treatments, are effective in prolonging the life of wood used in the garden. The degree of protection is governed largely by absorptions and penetrations; 20-minute dip or soak treatments are superior to brush treatments. Timber should be seasoned and fully manufactured, as dressing or cutting subsequent to treating may expose untreated surfaces. In addition treatments of aqueous solutions of Wolman salts, which give complete penetration, are available from some timber merchants. The timber should be painted afterward if long-lasting protection is required, or there may be some loss in effectiveness owing to leaching. Coal-tar creosote is an effective wood preservative, but may damage plants, as, under certain circumstances, treated wood may give off damaging fumes for many months.

Work for August z 4 4 n4--v»4 z-»4r* A n rfncl

In most districts August is regarded as the first / month of the new garden- / ing year, but there should j still be no urgency to sow or {riant extensively. Operations should be governed by the state of the soil and the weather. Green crops should be dug under, as a heavy green crop takes some time to rot ■ down after being turned in. The value of lupins as a green crop has long been

recognised, but to obtain full benefit from them digging in should not begin until there is considerable development of nodules on the roots.

Vacant areas should be dug over and dressed with lime if not already limed this year. Average New Zealand soils require an annual application of lib. a square.yard of carbonate of lime for vegetable growing. All growing crops should be hoed frequently to aerate the soil and to prevent weeds from growing. Crops of cabbages and cauliflowers should be kept mounded up to maintain the ridges they were planted on. Peas if supported with small sticks or with string stretched along each side of the row will not only crop more , heavily but will be of better quality and will be less likely to be eaten by birds. : In a well-planned garden a considerable area of ground should have been dug or trenched in autumn or winter and left rough. The first thing to be done before sowing in spring is to fork . over the top spit and break it down thoroughly. Light soils require only a shallow forking, as they readily crumble to a fine tilth if they are in condition for sowing. With heavy soils sods may need breaking up with the back of the fork. Firming and Raking The soil should be firmed before sowing or planting is done. Soils that are heavy or only just dry enough must not be firmed too much; hitting the earth with the back of the spade is sometimes sufficient. Soil that is in

the best condition for sowing should be firmed by walking along the rows with a shuffling motion. . .. The final work required to be . done on the seed-bed is .to remove lumps, stones, or rubbish and to level the soil and to. reduce it to the finest tilth possible by raking it with-., a finetoothed garden rake. The most convenient tool‘for making seed drills is an ordinary s van-neck hoe. To draw a narrow, deep drill the blade may be tilted and only a corner used.: If a wide, flat drill is required, the broad edge should be used. For very shallow drills the back of a rake pressed into the soil is sufficient. The maintenance of correct,, even depth is very important, because variations are likely to cause irregularity of germination, which will make thinning difficult or' result in blank spaces in the rows. Sowings The advice on the seed packet regarding the depth to sow is only a guide. In very light soils seeds , may be sown a little deeper than recommended and in damp or heavy soils a little shallower. Most seeds of . good quality have a high germinating capacity and should be sown thinly and evenly. Peas can now be sown in all except very cold districts such as South Otago, where sowings are best delayed until the. end of August or early September. Among the varieties suitable for early sowings are William Massey and Little Marvel.' ' ■

Potatoes: A first-early planting may be made in sheltered, frost-free areas in the:North Island. Popular varieties for early planting are Arran Banner and Epicure. Parsnips may be sown in the North Island in all except fairly cold districts. A good variety is Hollow Crown ’ Beetroot, carrots, turnips: Small sowings may be made in most districts, provided soil conditions are favourable. . Good varieties are: — . Beetroot: Crimson Globe, Detroit Red. Carrot: Early Krop, Early Horn, Chantenay. Turnip: White Stone. ■ The following may be sown in cool frames dr boxes with a glass covering for planting out later: — Lettuce: Imperial 615 or Neapolitan. Cabbage: Golden Acre, Enfield Market, and Copenhagen Market. Tomatoes (all districts): Dwarf, Adelaide Dwarf, Early Chatham. -Tall: Potentate, Moneymaker, or Carter’s Sunrise. Radish, spinach, and spring onions (sheltered, sunny positions): Radish: French Breakfast, White Icicle. Spinach: A prickly-seeded (winter) variety. Spring onion: White Lisbon. Plantings Cauliflower can still be planted in Auckland and Northland. Suitable •varieties are Early London and Phenomenal Early. ■ Cabbage may be planted in favoured localities. Recommended varieties are Golden -. Acre, Enfield Market, and Henderson’s Succession. . . Shallots: Now is the best time to plant shallots. Bulbs should be broken into the small natural division (cloves) and these pressed lin. into the ground in drills Bin. apart. ■ Onions for a main-crop for storing can be planted. A good keeping variety is Pukekohe Long Keeper. Asparagus and rhubarb: One- or two-year-old crowns should be set out without further. delay. Good varieties of asparagus are Paradise and Mary Washington, and of rhubarb Victoria Giant, Champion, and Topps Winter; the last will produce stalks all the year round, but is especially adapted to winter production. Many varieties are dormant in winter if the weather is fairly severe. Kumaras are grown mainly in warmer, relatively frost-free parts of the North Island. They may be raised in a box during August or early September. The box should be about Sin. deep and a convenient width and length and filled with , equal parts of good soil and sand. The tubers are set about 3in. deep and should be kept moist. The necessary soil warmth to promote growth may be induced by placing the filled box in a sunny position and covering it with a sheet of glass. The tubers shoot from the eyes and as soon as the shoots have developed small roots the shoots should be removed and planted in their permanent position or replanted into another box until required. If plants are removed early, another batch of plants will soon appear; 6 to 12 medium-sized tubers will supply enough plants for the average home garden.

New Type of Bird Scarer K/|ODELS of a' new'type of bird scarer devised by Mr. H. G. Perks, a . gardener ■*B, . of North-east Valley, Dunedin, have .'been kept under constant observation during the past. season by officers of the . Department of Agriculture ' to' ascertain their-efficacy in ' keeping birds off vegetable and other gardens.

The models were cut from 'an opened-out petrol tin and were shaped to represent a hawk in , flight. They are long with a 22in. wing span and are painted with dark brown- varnish. Each scarer has a. wire ring on '.the top centre of .the body for attaching it to a pole or wire. Because of the thinness of the tin used, the scarers reverberate with a faint "thundering" noise in the wind. Observation has shown that they are most effective in windy weather, when the vibration of the wings makes them realistic, but the birds become used to them and in calm weather.will feed quite close to them. A prominent strawberry grower in the Dunedin district who co-operated with the Department in testing the bird scarers Considers that they are the best of their type, but that there is nothing to equal a gun for keeping birds off gardens.