25) Plastic foil at the roof over peppers or tomatoes

In this tip:

  • Introduction
  • A)# Roof with adjustable sides of plastic foil
  • B)# End view and inside view
  • C)# Opening clamp, taking out, putting in.
  • D)# Short laths
  • E)# Closing lower and making storm proof
  • F)# Closed ends
  • G)# Shifting
  • H)# Closed plastic foil or perforated tunnel film
  • I)# Hanging wide
  • J)# How to make
  • K)# Laying foil on the roof
  • L)# Storm proof


You can put sweet pepper plants and tomato plants onder a roof of transparent corrugated plate.  In  Tip 7  some roofs have been described.



Tomatoes grow well in a backyard garden. Plant them in the open air or under an “open”roof. An open roof has no shields at the sides. Under an open roof the temperature is somewhat higher than in the open air.

In an allotment garden there is a big risk of the plant disease Phytophthora. So it is hard to make a good roof for tomato plants in an allotment garden. More info about my roofs in   tip 7  .


Pepper plants

In a good climate you can grow (sweet) peppers in your garden in the open air. In late summer, early fall you can have 3 or more big green peppers per plant. More info in        tip 9   , at I)# Sweet pepper plants growing in the open air or in a greenhouse.

You can put pepper plants under an open roof of transparent corrugated plate. More info in   tip 7  .

At an open roof, you want to have a shield at the sides too to shield the plants at cold, rainy weather. You can hang a piece of plastic foil over the roof and remove it at warm weather. But at windy weather this foil strikes the plants or the foil is blown away.

Next construction is better.


A)# Roof with adjustable sides of plastic foil

This is the open roof (arc roof of corrugated plate) of tip 7. Pepper plants can be put under it. The roof has 3 supporting vertical laths (legs) that are in the soil.

Over the roof there are 2 “pieces” of plastic foil; one over the left half and one over the right half of the roof.  In the middle they overlap about 4 inch. At each piece of foil, the ends of the foil are rolled up at wooden laths. The laths with foil are connected to short laths. These short laths are fixed to the 3 vertical laths of the roof.

On this photo foil has been “removed” at the right half.  This has been done by rolling up more plastic foil.

On this photo, left and right half have been opened by rolling up both pieces of foil.

Side view of the roof with pepper plants. You see the vertical laths (legs) and the short laths between these legs and the laths with rolled up plastic foil. The short laths are fixed to the legs by bolts and wing nuts.

Each long lath with rolled up plastic foil is fixed in a clamp at one end. My old clamp is a white plastic one with a metal strip (see top photo of the photos above). My new (simpler) clamp has been made of a sawn through metal corner brace (see lower photo of th ephotos above).

In each lath with rolled up foil there is a screw at the other end. During rolling up, this screw turns in a small hole in a short lath.


B)# End view and inside view

The plastic foil has been rolled off until “below”. You can look under (in) the roof. The short ends of the roof are still open.

Further, in F)# there is a description of removable end sheets. When end sheets are fixed, it is some warmer under the roof.

Inside view under the roof.


C)# Opening clamp, taking out, putting in.

At one side, each wooden lath with foil is in a clamp. The lath can be taken out. After rolling up or off some foil the lath can be put back in the clamp again.

Next some photos about taking out, rolling up and putting back. Photos of my old design clamp. But my new design works well too.


A metal “clip” keeps the lath with foil in the clamp.

The white plastic clamp has been opened by pulling and rotating the metal clip.

Here the lath with foil has been removed from the clamp (and laid on a  laundry-basket for the photo).

The lath has been turned and more foil has been rolled up. Therefore the short lath with clamp must be turned. The long lath has been put into the clamp again. The lath is not yet fixed in the clamp.

The white plastic clamp has been closed by pulling and rotating the metal clip. Now the lath with foil is fixed again.


New design of clamp

On these photos you see the old clamp (at the top) and the new model clamp (below). On the left photo, both clamps are open. At the righ photo they are closed.

The new clamp has been made of an iron corner brace. At one side a short part has been sawn off. The brace and the sawn off piece have been mounted on a wooden lath. The sawn off piece can turn and makes the clamp open or closed.

On these photos you see how the new clamp is used. The new clamp works as well as the old one. But the new one is easier to make. See chapter L)#.


D)# Short laths

There are 2 types of short laths.

  • short laths with a clamp at one end (to fix a long lath with rolled up plastic foil),
  • short laths wit a round hole at one end (to let the long lath turn).

Short lath with clamp;

At this roof there are 2 pieces of foil. This photo shows the overlap. The lath at the left side is  “lower” than the lath at the right side. In this way the laths and the foil will not collide or ravel.

The construction is as follows:

Each short lath has been fixed to one vertical leg of the roof. In each short lath there are 4 holes next to each other. Using one of the 4 holes makes the short lath more or less protrude. And makes the long lath with foil move more or less outwards.

On this photo: the short laths in front protrude less than the short laths at the back.


Short lath wit a round hole;

In each lath with rolled up foil there is a bolt at one end. This bolt is put in the round hole of a short lath. A nut and a wing nut prevents the bolt from going out of the hole. During rolling up or off, this bolt turns in the short lath.


E)# Closing lower and making storm proof

With extra holes in the vertical laths, the short laths can be fixed at a lower position. Then 2 rows of plants fit well under the foil.

Before storm , you can fix the short laths using these iron pins.


F)# Closed ends

On this photo a shield made of 2 wooden laths and thic plastic foil. Below a description.



  • Thick plastic foil. For each end you need about 1 square meter. Price in Europe is €7.00 for 2 square meters.
  • Wooden laths, about 4 cm (1.6 inch) wide and 1.5 cm (0.6 inch) thick. For each side of the roof 2 laths of 45 cm (1 ft  6inch) and 2 laths of 70 cm (2 ft  3 inch).
  • Wood screws or chipboard screws..
  • 2 Big wood screws with big heads.
  • 2 Screw eyes.



  • Lay two laths of equal length on each other. Drill small holes in both laths.
  • Use a thicker drill to make these holes bigger at 1 lath.
  • Bolt in (chipboard) screws in the lath with the biggest holes. Bolt in only about 1 cm (0.5 inch).
  • At 1 long lath with screws in, bolt in 2 screw eyes. Each screw eye about 7.5 cm (3 inch) from the end. Do not bolt in too deep.
  • At the long laths, drill 2 holes of about 8 mm (1/3 inch). Holes are about 7.5 cm (3 inch) from the ends and around 1 cm (0.5 inch) from one long side.


Fastening the top laths:

  • Bolt 2 big wood screws in the horizontal lath above. “Hang” the “back side lath” on these 2 screws.

  • Hold the foil on top at about the right position against the back side lath.
  • Push the “front side lath” against the foil. Bolt in the middle screw until almost tight. Now the foil is hanging at 1 position. The foil can still be turned. The “front side lath” is slanting.

  • Pull both short laths a little forward.
  • Turn the “front side lath” until it is in the same direction as the back side lath.
  • Turn the foil until it is hanging correct.
  • Bold all (3) screws in the short laths tight to hold the plastic foil between these laths.
  • Prick a screwdriver or an awl in the big holes of the frontside lath to make holes in the plastic foil.
  • Hang up the short laths with foil on the roof.


On this photo you see how the upper short laths hang on the big screws. They can not fall off so easily.


Fastening the lower side:

At the lower side, hold the foil between two long laths. Take care that these laths are about in the middle and horizontal.

Bold the screw eyes tight in the laths. Fix the lower side of the foil; push iron pins through the screw eyes into the garden soil.


Fixing the loose ends of the foil

Cut some plastic foil at the top sides to have it better fitting to the corrugated plate.


You can fix the loose lower flaps of the foil with iron pens.

Make a square hole in the foil. (fold up the foil, cut a half round or triangular hole, open the foil again). Push an iron pen through the hole and into the soil.


G)# Shifting

Each piece of plastic foil can be shifted over the corrugated plate. In this way you can open the front side of the roof and close the back side.

Or to correct when the foil hangs “oblique”.  Lift one long lath with foil and meanwhile carefully pull the other long lath down.


H)# Closed plastic foil or perforated tunnel film

You can use perforated tunnel foil or closed plastic foil. Perforated foil is easier to roll straight on a long lath (following the holes). But this foil starts tearing after a few weeks (or months) of use.

Closed foil is thicker and more rigid than perforated foil. But rolling up closed foil (in a straight way) is a little bit harder.

You can store “not used foil with 2 long laths” in the top of the roof,  just below the corrugated plate.


I)# Hanging wide

You can hang the foil more or less broad over the roof.

On this photo the foil is broad at the right side of the roof and narrow at the left side.


J)# How to make

Needed for the roof:

  • Transparent plastic foil, closed foil or foil with holes in it. Length 6 meters (6.5 yd).  Width depends upon the length of the roof.
  • Wooden laths, about 4 centimeters (1,5 inch) wide, 1,5 centimeters (5/8 inch) thick.
  • Iron corner braces, wood screws.


J1) Clamps new design


  • Iron corner braces.
  • Wood screws or chipboard screws.
  • Black tap washers.

Below photos and a description.

Saw off a piece from one leg of a corner brace. File the sharp metal burrs. Use a short lath, both parts of the brace, one washer and some screws to make up the clamp. Turn the screw throug the washer tight so the “iron strip” will turn heavily.

Fasten the clamp on a short block of wood, about 20 x 45 millimeter diameter and 10 centimeters long (0.8  x  1.8  inch,  4 inch long).


You can fix the short block of wood with clamp on a short lath (with 2 wood screws). More info about the short laths in L2) Short laths.

(It can happen that the short block of wood bursts when fixed to the short lath. To prevent bursting you can:

  • use a longer short block of wood,
  • use thinner wood screws,
  • predrill the screw holes or
  • fix the iron clamp on a short lath itself (not using a short block of wood).)


J2) Short laths

For each piece of plastic foil hanging on the roof, you need 4 short laths; 2 short laths with clamps and 2 short laths without clamps.

J2a Short laths with clamps

A short lath is about 4 centimeters wide, 1.5 centimeters thick and 52 centimeters long     (1  39/64 inch wide,  19/32 inch thick and  1 ft  8 1/2 inch long). Sizes are not critical.

There are 4 holes drilled in the lath. Hole size is about 5 millimeters (1/5 inch). Holes at 4, 8, 12 and 16 centimeters from the (left side) end. Hole positions are not critical.

The short block of wood with clamp is fixed to the short lath (right side on photo).

You can use the same design (short lath with clamp) for fixing long laths with rollled up plastic foil at both sides of the roof. By “turning” the short lath you get the clamp for the other side.


J2b) Short laths without clamps.

This lath has the same size as a short lath with clamp.

There are 4 holes drilled in the lath; the same size and distances as at the lath with clamp.

Near the right side end of the lath there is a round hole drilled, diamter 5 millimeters (1/5 inch). The bolt in a long lath with rolled up foil fits in this hole.

When you have 2 pieces of plastic foil on the roof, the short laths of one foil touch the other foil during “rolling up or down”. Sharp edges of the short lath can damage the foil. You better saw and round off the corners of the short laths to prvent this.


J3) Long laths

At a short roof with one piece of plastic foil, each long lath is about as long as the roof. At a long roof with 2 pieces of plastic, each long lath is about half of the length of the roof. Width and thickness of the long laths are about equal to the widt and thickness of the short laths. The widt and thickness are not critical, but a long lath with rolled up plastic foil must fit in a clamp.

At one end of each long lath there is a stick screw put in. A nut and a wing nut can be put on later. You can predrill and/or use lubricant when fixing the stick screws in the long laths.


J4) Fixing foil to the long laths

Below a description and photos how to cut and roll up plastic foil on long laths.

Plastic foil can be sold with a width of 6 meters. Each piece of foil must be about 2.25 meters wide. A length of 3 meters is enough to hang on both sides of the roof (and to roll up).

So with plastic foil of 6 x 2.25 meters you can make 2 pieces of foil.

Unfold the plastic (6 x 2.25 meters) until you see the begin and end. Lay the foil on a lawn or so.

Fold the foil in two (to get 3 x 2.25 meters). Lay a brick or so on each corner where 2 loose ends of the foil meet.

  • Use a long lath. Remove the stick screw from the lath.
  • Lay the lath “in” the fold of the plastic foil.
  • Pull taut the plastic foil.
  • Use a sharp knife to cut the foil at one short side of the long lath.
  • You end up with 2 pieces of plastic foil, each 3 x 2.25 meters.
  • At each piece of foil; the cut end and the opposite end are straight and parallel.

  • Lay one piece of plastic foil on the lawn.
  • Lay one long lath on the cut end of the foil. Lay the lath “in te middle of the foil”.
  • Fold the end of the foil over the long lath and put a (blue) thumb tack through the foil in the lath.
  • (By extension you can lay a short lath on the foil. This eases rolling up later).

  • Repeat these steps at the other end of the same long lath (yellow thumb tack).
  • Put extra thumb tacks through the foil in the lath between the 2 thumb tacks; distance between tacks about 40 centimeters (1.3 ft).
  • Let this long lath with foil lay on the lawn.

Go to the other end of the foil.

Lay the other long lath on that end of the foil. Fix the end of the foil to the long lath on the same way.

  • By extension you can lay short laths on the foil, one short lath at each end of a long lath. This eases rolling up later.
  • Carefully roll up 1.5 meters of foil at each end, until both long laths meet in the middle.
  • Check if the foil has been rolled up straight (the sides of the foil are about at the same position). If not, unroll one side, adjust and roll up again. Adjusting can mean taking out thumb tacks, shifting foil, putting in thumb tacks again.

  • Use an awl to make a hole in the plastic foil;
    • Near the 2 ends of each long lath. So 4 positions in total.
    • You can use the length of the short laths to calculate and measure those points.

  • Roll of a piece of foil. Check if the tiny holes in the foil are clearly visible.

  • Unroll the foil at both sides.
  • Use sharp scissors to cut the plastic foil next to the tiny holes.

  • Roll on the foil again, each side about 1.5 meters.
  • Put the stick screws in the long laths again.

The photo above shows that the foil has been rolled up straight. The foil is some narrower than the length of the long laths.


K)# Laying foil on the roof

Lay 2 long laths with rolled up foil in the middle of the roof. Do this at calm weather. Unroll the foil at one side for about 10 to 15 inch. Fix the long lath in the clamp and put the stick screw in the hole of a short lath. Put a nut and a wing nut on the stick screw.

Then unroll the foil at the other side and fix the long lath to the other clamp and the short lath (stick screw in hole, nut and wing nut on).

Fix the second piece of foil in teh same way when you have a long roof with 2 pieces of foil.

Adjust the foil at all sides of the roof to the desired height.

L)# Storm proof

The roof and the plastic foil have are been damaged by hard wind. The foil was tightened by the weight of the long laths.

When needed you can fix the short laths using metal pens in the soil, as shown on the photo above (see green handles just above the white clamps).


6 thoughts on “25) Plastic foil at the roof over peppers or tomatoes”

    1. Hello Seth,
      Thanks for your reaction.
      This is how; Put one leg of the corner brace horizontally in a vice bench. Pull on working gloves. Push with your hand against the “upright” leg of the brace. Push until that leg has been bended horizontally. When needed tap with a hammer.

      The clamps “new design” are easier to make and just as good. I added new tekst to the tip.
      greets, Sjef

  1. Sjef, thanks for this article. I already had a system slightly resembling yours, but this one is awesome. I will definitely install this one this year.
    Thanks for the idea and clear explications.

    1. Hi Marcel,
      You’re welcome.
      I use this roof mainly for sweet peppers in my allotment garden.
      The roof with plastic foil is rather sturdy. The roof or foil never blew away.
      I used the same plastic foil for 2 summers, one after another. And it was still okay.
      Good luck.

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