Windowed shelter for plants

A shelter for protecting young plants has a shell (10) made from a translucent resin material. Windows (28) are formed through a peripheral wall (16) on one side of the shell (10) for controlling the admission of light and air into the shelter. A hood (30) made from a transparent film of resin material covers the windows (28) to conserve heat and moisture within the shelter. The young plants are acclimated to their surroundings by progressively removing the hood (30) from the windows (28).

BACKGROUND 
Plant shelters protect young plants against early frost, damaging wind, 
unseasonably cool weather, heavy rain, hail, excessive sunlight, and 
insects and other pests. In addition, heat and moisture are conserved 
within the shelters to provide an environment that promotes the growth of 
young plants. The protections and controlled environment allow for earlier 
plantings that significantly extend growing seasons, especially in cold 
climates. 
Eventually the shelters are removed to allow the young plants to grow to 
maturity. However, the abrupt removal of the plant shelters can subject 
the young plants to considerable stress. Accordingly, some plant shelter 
designs control ventilation for gradually acclimating or "hardening" young 
plants to their surroundings. 
For example, U.S. Pat. No. 74,879 issued to R. M. Bartlett more than a 
century ago discloses a plant shelter having a conical shell made from 
pasteboard or thin wood and having two sets of openings. One set of large 
openings is covered with an oil paper, muslin, or glass for admitting 
light into the shelter. Another set of small openings is covered by a 
rotatable collar having a similar set of openings that can be variously 
aligned with or offset from the set of small openings in the cone-shaped 
hood for controlling ventilation within the shelter. Additional 
ventilation is provided by raising the hood on a pole as the protected 
plants continue to grow. 
Most subsequent plant shelter designs for controlling ventilation have 
generally followed Bartlett's approach of providing rigid relatively 
movable parts for adjusting opening sizes. Examples of such designs are 
found in U.S. Pat. No. 3,093,930 to Witkowski; U.S. Pat. No. 3,226,881 to 
Garrett; U.S. Pat. No. 4,392,326 to Boria; and U.S. Pat. No. 4,711,051 to 
Fujimoto. The multiple parts of these designs add cost, and the varying 
size openings also affect the amount of light admitted into the shelters. 
An alternative approach to controlling ventilation in plant shelters is 
disclosed in U.S. Pat. No. 3,214,865 to Rosenvold et al. The alternative 
plant shelter is formed from a transparent or translucent plastic material 
that is perforated for forming a series of knockout sections. Ventilation 
openings are formed by removing the knockout sections. However, once 
formed, the ventilation openings are permanent, and a new shelter is 
required to reduce ventilation. 
U.S. Pat. No. 1,814,339 to Sato discloses a plant shelter that provides for 
separately controlling the admission of air and light into the shelter. 
Ventilation is controlled in the usual way with an adjustable cap covering 
an opening. The shelter is made from glass for admitting light. However, 
one side of the shelter is made thicker with corrugations that are 
intended to diffuse light and heat. The corrugated side can be rotated 
toward or away from the source of light to block varying amounts of light 
from entering the shelter. In addition to requiring multiple rigid parts 
for controlling ventilation, the glass material is heavy and subject to 
breakage. 
SUMMARY OF INVENTION 
Our invention relates to an improved plant shelter that provides for 
independently controlling the admission of light and air through common 
windows. A reusable part forms a rigid structure with windows, and a 
replaceable part forms a transparent film covering the windows. The film 
can be progressively removed or penetrated to adjust the amount of air 
admitted through the windows without significantly changing the amount of 
light admitted through the same windows. 
Generally, our invention includes a dome-shaped body or shell molded from a 
resin material. Windows are formed in a peripheral wall of the shell, and 
a transparent film of resin material covers the windows. The transparent 
film can take different forms. 
For example, the transparent film can be formed as a hood that fits over 
the shell for covering the windows. A band secures an open end of the hood 
to the shell. However, the open end can be rolled up about the band for 
adjusting the amount of air admitted through the windows. 
The transparent film can also take the form of a sheet of self-attracting 
material that is wrapped about the periphery of the shell. The film is 
overlapped along a portion of the periphery for securing the film to the 
shell. The admission of air into the shelter is adjusted by progressively 
perforating a portion of the film that covers the windows. 
The shell is preferably made of a translucent material for reducing the 
amount of direct sunlight that is allowed to enter the shelter. The 
windows are preferably limited to an area that includes approximately 
one-half of the peripheral wall. The amount of direct sunlight that is 
allowed to enter the shelter is adjusted by rotating the shelter windows 
toward or away from the sun. However, the windows are shaped for admitting 
sunlight for extended periods throughout a day.

DETAILED DESCRIPTION 
Our preferred plant shelter has a dome-shaped body or shell 10 as depicted 
in the first four drawing figures. The shell 10, which can be molded from 
a translucent resin material, has an open end 12, a closed end 14, and a 
peripheral wall 16 that surrounds an interior space. 
The open end 12 is surrounded by a flange 18 that is reinforced with ribs 
20. Soil can be packed over the flange 18 to hold the shell 10 in place. 
The closed end 14 has a rounded portion 22 for shedding water and a flat 
portion 24 for affixing an appropriate logo. The peripheral wall 16 is 
formed as a conic section centered about an axis 26. In addition, the 
peripheral wall 16 is inclined with respect to the central axis 26 through 
an angle between approximately two degrees and ten degrees to permit the 
shell 10 to be nested with similar dome-shaped bodies for conserving 
storage space. 
Windows 28 are formed through the shell 10 within a limited area of the 
peripheral wall 16. Preferably, the windows 28 are limited to an area 
extending throughout no more than one-half of the perimeter of the 
peripheral wall 16 so that all of the windows 28 are positioned on one 
side of the shell 10. This arrangement allows the windows 28 to be rotated 
about the central axis 26 either toward or away from the sun to adjust the 
amount of direct sunlight admitted into the shell 10. 
Each of the windows 28 is dimensioned by orthogonal measures of a height 
"H" and a width "W". The height "H" extends generally in the direction of 
central axis 26 and preferably exceeds the width "W" by a factor of three. 
The prescribed ratio of height "H" to width "W" allows direct sunlight to 
enter the shell without interruption throughout early or late periods of 
the day, when the sun is near the horizon. However, the relatively slight 
angle between the peripheral wall 16 and the central axis 26 protects 
young plants from direct sunlight at midday, when the sun is highest in 
the sky. 
FIGS. 5 and 6 show the shell 10 at least partially covered by a similarly 
shaped hood 30 made from a transparent resin film. The shell 10 and hood 
30 complete a first example of our new plant shelter. Like the shell 10, 
the hood 32 has an open end 32, a closed end 34, and a peripheral surface 
36. The open end 32 is secured to the shell with an elastic band 38, which 
can be made of rubber or similar material treated to withstand direct 
sunlight. 
The closed end 34 and peripheral surface 36 of the hood enclose the closed 
end 14 and peripheral wall 16 of the shell 10. The peripheral surface 36 
of the hood, as shown in FIG. 5, also covers the windows 28. The elastic 
band 38 seals the open end 32 of the hood to the shell 10 to trap heat and 
moisture within the plant shelter. 
The hood 30 can be progressively removed by rolling up the open end 32 
about the elastic member as shown in FIG. 6. Young plants can be gradually 
acclimated or hardened to the surrounding environment by periodically 
rolling up the hood 32 to uncover increasingly large areas of the windows 
28. Since the hood 30 is transparent, uncovering the windows 28 has no 
significant effect on the amount of light that is admitted though the 
windows 28. 
The plant shelter of FIGS. 5 and 6 is used for promoting the growth of 
young plants by covering the young plants with the shell 10. Soil is 
packed over the flange 18 to secure and seal the shell to the ground. The 
open end 32 of the hood is fit over the shell 10, completely covering the 
windows 28. The elastic band 38 is also fit over the shell 10 to secure 
and seal the open end 32 of the hood to the shell. 
The hood 30 traps heat and moisture within the shell 10, providing a 
controlled environment for promoting early growth of the young plants. The 
amount of direct sunlight admitted through the windows 28 is adjusted by 
rotating the plant shelter about the central axis 26 to control the 
orientation of the windows 28 with respect to the path of the sun. 
When the young plants are sturdy enough to survive in the surrounding 
environment, the open end 32 of the hood is rolled up about the elastic 
member 38 to uncover a small portion of the windows 28. This allows a 
limited amount of air circulation between the interior space of the 
shelter and the surrounding environment. Following periods of adjustment, 
the windows 28 are progressively uncovered in a similar manner to further 
acclimate the young plants. Finally, the plant shelter itself is entirely 
removed to allow the young plant to grow to maturity. 
A second example of our new plant shelter is shown in FIGS. 7 and 8. In 
place of the hood 30, the shell 10 is covered with a sheet 40 that is made 
from a transparent resin film. The sheet 40 is wrapped around the 
peripheral wall 16 of the shell, completely covering the windows 28. The 
resin material of the sheet 40 is preferably self-attracting, and the 
sheet 40 is overlapped along a portion of the peripheral wall 16 to secure 
and seal the sheet 40 to the shell 10. 
The plant shelter of FIGS. 7 and 8 can be used to similarly promote the 
growth of young plants. For example, the young plants can be covered with 
the shell 10, and soil can be packed over the flange 10 to hold the shell 
on the ground. However, instead of placing the hood 30 over the shell 10, 
the sheet 40 is wrapped around the peripheral wall 16, enclosing the 
windows 28 to conserve heat and moisture within the shelter. 
The young plants are acclimated by progressively perforating enlarged areas 
of the sheet 40 within the windows 28. This can be accomplished by using a 
sharp instrument to puncture or tear the sheet 40. Initially, only small 
openings 42 are made in the sheet to permit a limited circulation of air 
through the windows 28. However, the size of the openings 42 is increased 
until the young plants are sturdy enough to survive in their surrounding 
environment. Since the openings 42 are made in a transparent material, the 
variation in opening size does not significantly affect the amount of 
light admitted through the windows 28. 
Although it is possible to use the hood 30 of the preceding embodiment more 
than once, the sheet 40 needs to be replaced after each planting cycle. 
The sheet 40 can be replaced with conventional plastic wraps that are 
normally used for wrapping food. For example, the sheet 40 can be 
unwrapped after use and the shell 10 can be rewrapped with another sheet 
cut from a roll of plastic wrap. 
Both the hood 30 and the sheet 40 can be tinted or otherwise treated for 
blocking particular wavelengths of light. For example, the hood 30 can be 
treated to protect the shell 10 and young plants from harmful ultraviolet 
light.